For years, Chessengeria.eu has been a hub for chess engine enthusiasts, offering rankings, analyses, tests, and reviews. To better meet your expectations and deliver more valuable content, I am implementing significant changes to the policies regarding engine participation in MCERL tournaments, as well as their compilation and distribution, effective immediately. Image generated by Darius using OpenAI's DALL·E 2 Image Generator Chess Engine Compilation – Focus on macOS (Apple Silicon) The primary focus of Chessengeria.eu is to support Mac computers with Apple Silicon processors (M1, M2, M3, M4, and newer). The engines I provide will be prepared for this architecture to ensure the highest quality and stability for users. All engines compiled by me will be labeled as: Compiled by chessengeria.eu Example: Engine Name - Compiled by chessengeria.eu The "Compiled by chessengeria.eu" tag will also be embedded in the engine's code and visible upon execution. This ensures that users can trust the engine's source and rely on its stability, aligned with the original project authors' intentions. This solution also ensures transparency, identifies the source of the compilation, and protects against misuse, such as lack of attribution or violations of open-source licenses. Additionally, it safeguards against unauthorized appropriation and supports version identification for engines. Support for Windows and Linux Engines Compilations for Windows and Linux will be provided only for modern processors (eg. avx2) and exclusively for leading engines that stand out in terms of capabilities and/or playing strength. Upon request, I may prepare dedicated compilations for specific operating systems and processors – please feel free to contact me if needed. MCERL – Higher Quality Standards and Chessengeria.eu Resources For years, Chessengeria.eu has invested significant resources into the development of MCERL. Thousands of hours have been spent conducting matches between engines, analyzing results, and creating rankings that are appreciated by users worldwide. The mission of Chessengeria.eu is to promote computer chess, which means maintaining high-quality engines – free from crashes and timeouts – is essential for providing users with the most reliable tournament results in MCERL. Therefore: All new engines must pass an initial crash test of 200 games before being admitted to MCERL tournaments. If an engine encounters even a single crash or timeout during this test, that version will be excluded from MCERL. For new engines admitted to MCERL, the stability rule applies: If an engine experiences 3 crashes or timeouts during a full tournament cycle (e.g., 2,000 games), that version will be excluded from MCERL. These measures ensure that MCERL remains a platform for stable and reliable chess engines, maintaining the high quality of its rankings. Why Am I Making These Changes? Image generated by Darius using OpenAI's DALL·E 2 Image Generator Modernity and Technological Trends: Mac computers with Apple Silicon CPUs have been widely adopted by millions worldwide, as evidenced by Chessengeria.eu statistics showing their continuous growth. Meanwhile, the number of users with Intel-based Macs and Windows systems has been steadily declining. The number of Linux users remains stable, with increasing interest in the ARM platform. Efficiency and Optimization: Focusing on a single primary architecture (Apple Silicon) allows me to better manage my time and resources, enabling the publication of more articles, tests, and reviews – in line with your suggestions. Ecology and Savings: Apple Silicon provides excellent performance while consuming minimal energy compared to traditional PCs, aligning with global pro-environmental trends. This aspect is also valued by many of you, as reflected in your feedback and correspondence. Protecting Work and Upholding Licenses: I have compiled and distributed hundreds of chess engines via Chessengeria.eu. These engines are governed by various open-source licenses that require, among other things, proper attribution, sharing source code, and including relevant project information. Unfortunately, I’ve noticed that these rules are not always fully respected, which undermines both the authors' rights and the collaborative spirit of the open-source community. Sharing chess engines via Chessengeria.eu adheres strictly to open-source license principles, which are fundamental to the modern chess engine community. I expect those using my compilations to respect these principles as well. MCERL favors engines released under open-source licenses such as GPLv2, GPLv3, or MIT, which promote transparency and openness. Engines without licenses or with closed-source code may be admitted only under the condition of explicit permission from their author and compliance with our strict quality and stability standards. What’s Next? Chessengeria.eu remains open to users of all platforms – offering universal information to support your work, learning, and enjoyment with chess engines and software. I invite you to reach out if you have any questions, suggestions, or requests for special engine compilations – your ideas and feedback are essential to this project’s growth. Thank you for your understanding and support, which enables Chessengeria.eu to continue developing and delivering even better content. Together, we are building a unique space for computer chess enthusiasts!

What's the best way to celebrate the end of 2024 in Chessengeria style? Of course, by organizing a tournament of the absolute chess engines Elite ;) Image generated by Darius using OpenAI's DALL·E 2 Image Generator Introduction of the 2024 Elite Chess Engine Tournament. The year 2024 was a remarkable one for the world of chess engines. Thanks to the relentless efforts of their developers, most of the most powerful engines have reached a new and much higher level of strength. To highlight the progress, let's consider the following: while in the 2023 edition of the Elite Tournament the minimum threshold for participation was 3500 CElo and the average score was 3626 CElo, the 2024 edition raised the bar significantly. The average CElo of participating engines rose to an impressive 3767 CElo this year. This underscores the rapid progress in chess engine performance in just one year. In 2023, 15 engines competed, the strongest of which was Stockfish 20231230 with 3845 CElo, and the weakest was Altair 6.0.0 with 3502 CElo. In the 2024 edition, the competition was even fiercer. Stockfish 17 topped the charts with an unmatched score of 3875 CElo, while the weakest "traditional" engine in the list, Caissa 1.21, registered an impressive 3725 CElo. Meanwhile, the lowest ranked "non-traditional" engine, Lc0 031.2, achieved 3692 CElo, benefiting from its unique features and capabilities. The difference in performance between Stockfish 17 and other engines remains noticeable, although the pace of development of Stockfish seems to have slowed a bit compared to 2023. All this, however, has opened up space for other chess engines to narrow the gap and showcase their progress in 2024. Here is the list of participants in alphabetical order: Here is the list of participants in order of Elo rating, from the strongest: The tournament was run under the terms of MCERL, that is: Time Control Adjustment for Lc0 Due to the nature of Lc0 , I allocated it twice as much thinking time compared to other engines. While all other engines were set to a time control of 1 minute per game + 0.6 seconds per move, Lc0 was given 2 minutes per game + 1.2 seconds per move. This adjustment reflects Lc0's reliance on GPU performance and its neural network architecture, which requires more time to reach optimal decisions. By doubling its time allocation, I aimed to provide a fairer comparison between Lc0 and the "traditional" chess engines in the test environment. It is worth mentioning that Lc0 makes better use of more time and resources than “traditional” chess engines, which, as you will see, will be reflected in the tournament results. Which chess engine will prove to be the winner? Participation criteria for the 2024 Chess Engine Elite tournament In order to keep the competition highly competitive and attractive, the Elite 2024 tournament introduced stricter participation criteria. Engines had to achieve at least 3683 CElo, calculated as 3808 CElo (the strength of Obsidian 14.0) minus 125 CElo. Obsidian 14.0 was chosen as the reference engine instead of Stockfish 17 because Stockfish's level of play (3875 CElo) is much higher than most other engines. Using Obsidian 14.0 as the benchmark provided a more balanced competitive environment, while allowing all of the tournament engines to compete effectively. The calculations (3808 CElo - 125 CElo = 3683 CElo) were intentionally designed to account for slightly weaker engines while remaining highly competitive. This approach also benefits engines such as Lc0, which perform exceptionally well given enough time to think. The participation criteria were also intended to promote the work of the chess engine development community and to promote our passion for computer chess with the latest versions of chess engines. Due to requests from some authors, only official versions of chess engines were invited to the Elit tournament - test and developer versions were not considered. It is significant that the Elites list of chess engines for 2024 includes only open-source engines. There are no commercial engines here, which underscores the fact that the collective involvement and work of entire communities are extremely effective in developing chess engines for the strength of their game. Moreover, eligibility for the most important tournament on our blog chessengeria.eu required active development in 2024. For example, Dragon by Komodo Chess (3737 CElo) did not participate because its development was undeniably completed, with the last version dating back to 2023. Similarly, Koivisto 9.0 (3693 CElo) was excluded, , as its last update was on January 15, 2023. The same goes for the Seer 2.8.0 engine. Which one will play the most interesting and spectacular game? New Platform for the Tournament This year's tournament was conducted on a new platform—the Mac Mini powered by the Apple Silicon M4 Pro processor. This hardware marked a significant upgrade from the Apple Silicon M1 used in the 2023 edition, offering enhanced performance and computational speed. The improved system allowed engines like Lc0 to fully leverage their neural networks on a macOS-powered Mac. Notably, Lc0 utilized the BT4-1740 network, one of the most powerful neural networks available, demonstrating its undeniable potential and achieving commendable results in this extraordinary chess engine competition. The same Mac Mini is currently being used for games in the MCERL cycle, providing a stable and reliable platform for intense chess engine tournaments. 28.528.719 Nodes/second in Stockfish 14.1 benchmark on Apple Mac Mini M4 PRO To ensure the highest quality and excitement during the matches while maintaining fairness, the tournament featured 220 games (each engine played four games against every other engine) instead of a 1000-game "grind," which might have disproportionately favored the strongest engines. This balanced format allowed all participants to showcase their strengths more effectively. Additionally, the superior and significantly more efficient hardware enabled engines to better utilize their advanced neural networks. Lc0's performance in particular stood out, leveraging the BT4-1740 neural network—one of the most powerful available—to demonstrate its potential and achieve impressive results in games against the strongest opponents. Curiosity - Performance comparison The computer used in the 2023 Chess Engine Elite tournament, the MacBook Pro M1, achieved a score of 12.278.776 Nodes/second in the Stockfish benchmark. 12.278.776 Nodes/second   in Stockfish 14.1 benchmark on Apple MacBook PRO M1 How did the old 2014 iMac do in this benchmark? 1.698.009 Nodes/second   in Stockfish 14.1 benchmark on Apple iMac Mid 2014 In the Stockfish 14.1 benchmark, Apple's ARM-based Silicon M4 PRO CPU is more than 2 times faster than the M1 CPU and more than 16 times faster than a 10-year-old computer with an Intel Core i5 (Haswell) CPU. Category: tournament winner - Stockfish 17 Here is the scoreboard of the Chessengeria's Chess Engines Elite Tournament - 2024 * Table with results created in Banksia GUI Stockfish and Obsidian didn't lose a game! Table with results created in Banksia GUI Congratulations to the Stockfish Team !! *** Download the database of all Chessengeria's Chess Engines Elite Tournament - 2024 games Compared to the results of last year's Chess Engine Elite tournament, Stockfish did not dominate the competition. The struggles were extremely exciting! Until the last round the fate of the first three best of the best was at stake :) Looking at the results of this tournament, which is what a unique event - only held once a year - I can say with satisfaction that all the objectives and criteria met the hopes. Although Stockfish won, it won the tournament just “by a hair” by half a point his victory was not certain until the last round. Alexandria performed impressively ahead of the theoretically stronger Obsidian. PlentyChess scored a very successful debut in this strongest chess engine tournament on the macOS platform. Lc0 showed that it can play successfully as an equal against the strongest opponents. All participants played games at an extremely high chess level, which made me very happy and gave me great satisfaction watching their struggles - which I would now like to share with you, dear reader. Category: Most Spectacular game. Do computer players at such a high level only play boring chess? Absolutely not! On the contrary, most games are beautiful works of art, and some of them - like the game presented below - are even a model example of magnificent sacrifices that sanctify the goal. White: Lc0 0.31.2 (BT4-1740) Black: Berserk 13 White's move. The position was created after 21 moves in the Spanish game. Both players have just completed the development of their pieces. The position is equal. Black has free figure play, although the price for this is a weak d6 pawn. White can start concentrating more forces on attacking the black d6 pawn or do what Lc0 chose to do in this game. It's time to move on the black King's position! ** Diagrams created in the ChessX Bh6 22... Bxh6 Qxh6 Ne6 As a result of the exchange of Bishops, the whites brought their Queen closer to the position of the black monarch. Did this give them an advantage? No, but it created opportunities for attack, especially since the black Queen is watching the course of events from afar. Ngf5!? A nice and quite brave move considering the class and strength of the opponent. A classic move in this kind of positions. 24... gxf5 Not accepting the Knight sacrifice led to an equal but uncomfortable position for black with the open position of their King. Example continuation: 24... Nh5 25. a5 Qc5 26. Nxe6 Rxe6 27. Bb1 gxf5 28. Qxh5 fxe4 29. Rd5 Back in the game. a5! Another sacrifice. This is an important interjection that forces an even deeper retreat of the Black Queen from the theater of events. If Berserk takes Pawn, the scales of victory will go to the side of Lc0 after a few moves: 25... Qxa5 26. Nxf5 Qe5 27. Rxd6 Kh8 28. Rxe6 Ng8 29. Rxe5 Nxh6 30. Nxh6 Rxc2 31. Nxf7+ Kg8 32. Rxe8 Bxe8 33. Nd6 With white's material advantage sufficient to win. 25... Qa7 Nxf5! Lc0 is consistent. For the price of an attack, it gives up the white Bishop. 26... Rxc2 Black has a material advantage in the form of two light figures. Let's take a close look at the position on the chessboard. The g7 square is effectively defended against checkmate by the black Knight. The inclusion of Rook putting it on the e3 square with the idea of strengthening the attack (Re1-e3-g3) is not good because 27. Re3 will be followed by a strong 27.... Nxe4! and after 28. Rxe4 Qxf2+ 29. Kh1 Qxg2# What can be done to stop black from invading their Queen on f2 square ? How should white continue the attack? Dear reader, you are traditionally invited to solve the chess puzzle. ...... .................. .................................... Rd4!! If you managed to find this move, congratulations :) This seemingly strange move is the most appropriate one. Berserk cannot take Rook using Knight because it will get checkmate. Exchanging the black Queen for this Rook and Knight is a mediocre idea, as white gets a free game with better chances. 27... Nh5! Berserk picks the best and most impressive continuation. Qxh5 Qc5 Re3 Nf4! Nh6+ Kh8 Nxf7+ Kg8 Rg3+ Ng6 Black defends the position of its King very well! Rxg6! 33... hxg6 Qxg6+ Kf8 Qh6+! Kxf7! Berserk takes another victim. Qh7+! Lc0 chooses the only move that ensures it a draw in this game. 36... Ke6 Qh6+ Ke5 Qg7+ Ke6 Qh6+ Kf7 Qh7+ Kf6 Qh6+ Ke5 Qg7+ Ke6 Qh6+ Draw. Lc0 played very bravely in this game sacrificing many of his figures. Thanks to its precise and calm defense, Berserk managed to fend off his opponent's strong and uncompromising thrust, leading to a well-deserved draw. I think this game can be enjoyed :) Download game: Most Spectacular Game Category: Most interesting game In this game we will not see fireworks and many spectacular moves. It will show you dear reader how an engine with more than 3800 CElo on the MCERL counter can win against a very strong opponent who does not make mistakes while playing chess in the human sense of the word. Winning - the Obsidian chess engine, will show how chess can be played beautifully with a deep strategic understanding of the position - from the first moves in the game. White: Obsidian 14.0 Black: Stormphrax 6.0.0 Blacks's move. The position was created after playing the opening of King's Indian variant Mar del Plata. In this setup, white intends to fight on the Queen's wing, while black seeks its chances on the King's wing. 11... a5? If I were analyzing a game of people, after this move I would probably write that 11... a5 is an interesting and active move designed to open up the A-line for the black Rook and activate their figures on the Queen's wing. Fortunately, I have the pleasure of analyzing the game of chess engines at a level unattainable for humans. Therefore, I will write that, in my opinion, 11.... a5 is a strategic error, and that's why I marked this move with a question mark. Black, instead of playing in the spirit of his chosen opening and continuing the assault on the King's wing, wastes valuable time maneuvering on the other side of the chessboard, where there is practically no activity of their figures - it is instead on the King's wing. bxa5 Rxa5 Black takes the white pawn - a waste of time - their Rook occupies a bad square - nothing to do here. Perhaps Stormphrax was hoping for an opportunity to strengthen the pressure on the A-line on Pawn a4 by putting their Queen or Rook on the a8 field, but it doesn't manage to do so. exf5! Obsidian at the best of times relieves the tension in the center by opening the diagonals b1-h7 and preventing any future uncomfortable closure of the position for the whites by moving black Pawn f5-f4 13... Nxf5 Bg5 Nf6 Bd3 b6 h3 Bd7 Ra3! Ra8 Black finally recognizes that they chose the wrong strategic plan and withdraws their Rook. White's move 17. Ra3! is not to reinforce the forces on the A-line and force a breakthrough through white Pawn's move a4-a5, but is to activate white's Rook and join the King's wing action quickly. Bc2 Kh8 g4 Ne7 Bc1 Ng8 Ng5 Bh6 f4! Obsidian opens another diagonale for its black-square Bishop : a1-h8 22... exf4 Nf3 Bg7 Bb2 h6 Qa1 The image on the chessboard is a testament to blacks choosing the wrong game strategy plan. Stormphrax failed to take advantage of the opportunities presented by it's chosen opening (storming the King's wing). Obsidian, on the other hand, correctly read the situation on the chessboard and changed it's game strategy accordingly. Strategically and at this level of the game - black has a mute losing position. Most of their pieces occupy the last line concentrating around their King with no prospect of any counterplay. 25... Rf7 Ne2 Qf8 Nd4 g5 h4 gx4 g5 White has a free play. All their pieces take optimal positions for the final assault of the black King's position. 29... Re8 Re2 h3 Re6! Despite the wily concentration of black pieces, white chooses the most impressive and effective end to the dispute on the chessboard. 31... c5 If 31...Bxe6 then 32. Nxe6 with the loss of the black Queen. dxc6 Nxc6 Nh4 Nge7 Rxh6 White Rook realizes the work of destruction! 34... Bxh6 Ne6+ Bg7 Nxf8 Rexf8 Be4 Na5 Bxg7 Rxg7 Qd4 Series of exchanges resulting in the loss of the black Queen and white leads to a completely winning position for them. 39... Nxc4 Qxc4 d5 Qc7 dxe4 Qxd7 h2+ Kxh2 f3 Kg1 Nf5 Qe5 Nxh4 Qh6+ Kg8 Qxh4 Rf5 Rc3 1 :0 After a few more moves, the game ended in victory for the whites. Watching the game live, I wondered where Stormphrax went wrong? What led to black being almost paralyzed by their opponent after choosing a known and proven opening? Having played by correspondence for many years, I came to understand that chess is not what it appears to be in the context of games played by people with even longer control time. In correspondence chess and also in chess engine games at that level, it is critical to understand the position and choose the right strategic plan. The implementation of the strategic plan - is a completely different and much simpler task. The most important thing is the strategy -> its selection. Obsidian 14.0 has shown that it ranks second (behind Stockfish) on the MCERL for a reason. Congratulations! Download game: Most Interesting Game How do chess engines win games at levels exceeding 3700 CElo MCERL ? Being positively moved by the playing style of Obsidian 14.0 and in the context of the games of other chess engines in the Elit tournament, you will find the answer to your question in the next article :) A Rewarding Experience Organizing and conducting the Elite Chess Engine Tournament brought me immense joy, and the results are truly inspiring. The ongoing evolution of chess engines in 2024 reflects the vibrant passion and determination of the chess engine development community. It is an honor to witness and document these milestones in the world of computer chess. The Elite Chess Engine Tournament stands as a testament to the brilliance and ingenuity that drive and will continue to drive the future of chess engines. Summary of the 2024 Elite Chess Engines Tournament. The year 2024 in the world of computer chess was extremely inspiring, and ending it in Chessengeria style brought unforgettable excitement to the Elite Chess Engines Tournament. This competition, held on the new platform with Apple's Silicon M4 Pro processor, not only highlighted the advances in engine development, but also provided spectacular duels in which advanced strategy was combined with the beauty of chess art. We sincerely congratulate the Stockfish team for the victory, as well as Alexandria, which caused quite a surprise by taking the honorable second place! We also congratulate all participating engines, whose creators showed tireless work and commitment. Special mentions go to Lc0 for its bold and artistic approach to each game and Obsidian for its outstanding strategy. We would like to thank the entire chess community - the developers, programmers, enthusiasts and readers of Chessengeria - for their support and motivation, which contributed to the success of this unique event. Your passion is key to the further development of this field. We are already looking forward to what 2025 will bring, believing that future tournaments will provide equally unforgettable experiences! * Participants in the Elit tournament played against each other through the Banksia GUI - A Free Chess Graphical User Interface. ** Diagrams created in the ChessX *** All games were prepared for download using Scid vs Mac - free chess toolkit with extensive database, analysis and chess-playing features.

At last? Hmmm.... Although the picture above shows a man smiling sympathetically, I am not laughing at the time of writing this post. It will be a rather short story about the power of Open Source, and while not as cheerful as the gentleman in the picture, it will probably have an optimistic ending... Anyway, decide for yourself :) The Fat Fritz 2 chess engine was sold until recently, although it was actually Stockfish with altered neural network. For readers less familiar with chess engines, Stockfish is a free open source chess engine under the GNU GPL 3.0 license. It is the result of many years of hard work by hundreds of people from all over the world. As a result, Stockfish is one of the strongest and maybe even currently the strongest chess engine on our planet. The aforementioned license permits commercial use of the software, but this must be done in accordance with the applicable provisions of the license. Quoting a post from the Stockfish blog : " (...) Fat Fritz 2 and Houdini 6 are based on Stockfish, and ChessBase infringed on the license by not distributing these products as Free Software in accordance with the GPL. Their customers have not received the necessary information, namely the text of the GPL license covering these programs and the corresponding source code of these programs, to exercise the rights granted by the GPL. These rights include the right to reproduce, modify and distribute GPLed programs royalty-free. " The open source chess community has greeted with outrage the actions of ChessBase GmbH, which sold Fat Fritz 2 - reaping tangible financial profits of the product, which was in fact based on free Stockfish. The case went to court with a lawsuit by the Stockfish Team. On November 7, 2022, a settlement agreement between the parties was published, from which sales of the Fat Fritz 2 program have been halted and, quote: "(...) Within eight weeks after the conclusion of this Settlement, Defendant shall, in order to improve compliance with license terms on Free and Open Source Software (FOSS), internally introduce the role of a "Free Software Compliance Officer" and list under the domain [ foss.chessbase.com ] the products that contain the software Stockfish under the GPL-3.0 or other FOSS. If the respective licenses require the provision of the source code, the Defendant will enable a download of the source code by anyone from there. Neural Networks offered by Defendant for use with Stockfish that are included in the compilation or dynamically loaded at runtime to initialize the data structures and logic of the Software must be subject to GPL-3.0 or a compatible license. " In short, the Fat Fritz 2 chess engine, based on a court settlement, became available under the GNU GPL 3.0 license along with the source code and the neural network. This means that anyone interested can use the software in accordance with the aforementioned license. So is the case with the Stockfish chess engine. GNU GPL 3.0 licenses (and others, such as LGPL 2.1) are documents - guarantees of the "freedom" of software. In vastly simplified terms, they stipulate that software released under such a license remains free and available to all. It is a violation of the license to attribute it or use it without meeting all the conditions included in the documents. It poses a danger to the integrity of the open-source community: it destroys the trust that is so vital in this environment. "Open source" does not mean something inferior, less valuable, because it's free. That's a myth. A much bigger problem with the use of this type of software is abuse. "Open source" is valuable software. Why? Because it is transparent. Anyone can have access, anyone can make changes, improve. And when it works according to specific and acceptable mechanisms, it can be successful - just like the Stockfish project , which brings together many committed and talented people. Furthermore, it is a good thing that thanks to the consistency and determination of people from the Open Source community in asserting their rights, the case went to court, the settlement of which strengthened the community. The conduct of ChessBase GmbH unfortunately has and will continue to have consequences: the trust of existing customers and potential customers has been damaged; the reputational damage will take many years to recover from, which could translate into financial results. What's next? ChessBase GmbH has begun to take care to meet the terms of the GNU GPL 3.0 license and has made the source code of Fat Fritz 2 and other software available at foss.chessbase.com. Other issues to be implemented by ChessBase GmbH are described in detail in the court documentation made available on the Stockfish website . I would like to point out that the topic is not only about the Fat Fritz 2 chess engine... We were still talking about the Houdini 6 chess engine, and I won't even elaborate on the Fat Fritz 1 topic, it's material for a separate entry; I'll just add that also Fat Fritz 1 is free to download from http://foss.chessbase.com/ chessengeria.eu is a blog that is visited by a lot of people every day, which is the result of thousands of hours of work to create it and fill it with content. For everyone and for free. And that is why I perfectly understand the Developers of the Stockfish chess engine, who worked for years on their creation. Sales of the aforementioned chess engines did not come by chance, of course. Marketing did its job, extolling what great, innovative and improved chess engines they are. It's very sad that ChessBase GmbH violated the terms of the GNU GPL 3.0 license and used open source software source code without even signaling it beforehand. As you can see, the temptation is sometimes too strong, especially when big money is involved. It's not that such open source software can't be used. You can, but you have to signal it and meet all the requirements that arise directly from the provisions of the license. As we already know, now Fat Fritz 2 is a free open source chess engine. I have prepared compilations of this engine for popular platforms. In addition to the source code, I have included documentation regarding this topic downloaded from the Stockfish webpage . Fat Fritz 2 was sold only in versions prepared for use on Windows computers. However, below you will find this chess engine also for Macs and 32/64-bit Linux and Windows. If you want, download and use it. Although, it might be better if you give the latest Stockfish or Lc0 a chance, they are 100% original, stronger and do not pretend to be anything they are not. That's the power of Open Source, don't you think? ;) Fat Fritz 2 source code – by Stockfish Devs and Albert Silver (neural network) Linux arm32 & arm64 & x64 – Compiled by Darius Mac Apple Silicon & Intel – Compiled by Darius Windows x32 & x64 – Compiled by Darius In the Files area you will find free chess engines for download.

Check out the latest MCERL from 2024! The best engines, no clones and results powered by Apple Silicon M4 PRO. Take the plunge and see what's new! Image generated by Darius using OpenAI's DALL·E 2 Image Generator I invite you to read the latest MCERL

You can't miss it... MCERL 2024-11-15. Image generated by Darius using Microsoft Bing Image Creator I invite you to read the latest MCERL

In the era of artificial intelligence domination on the chessboard, the boundaries of chess engine capabilities continue to expand. At levels exceeding 3700 CElo within the MCERL rating, the top chess engines display not only superhuman precision but also creativity reminiscent of artistic mastery. Image generated by Darius using OpenAI's DALL·E 2 Image Generator How do they achieve such remarkable results? Are their victories solely the product of brute computational power, or do they embody a deeper understanding of chess? In this article, we uncover the secrets behind the strategies and technologies driving modern-day masterful algorithms. To delve deeper into the mechanics behind these exceptional performances, we will analyze several games from the Chess Engined Elite 2024 Tournament . This choice is deliberate, as the tournament showcased engines operating at peak levels, with each move meticulously calculated to outwit their opponents. By examining these games, we can uncover patterns, strategies, and decision-making processes that illustrate how engines not only leverage computational power but also demonstrate an almost human-like intuition and creativity in critical moments. This analysis aligns perfectly with the article’s focus on understanding the artistry and precision behind victories at levels exceeding 3700 CElo. Game 1 - Dancing with weaknesses. White: Alexandria 7.1.1 Black: RubiChess 20240817 White's move. * Diagrams created in the ChessX The position is equal and was created after 18 moves in the opening: Two knights defense (Modern bishop's opening). bxc6! Alexandria aims to create vulnerabilities to exploit and weaken RubiChess' position. 19... Nxc6 Nf5 Ne5 Bb2 Ned7 Ba1 b6 f3 Qc6 There are two weaknesses in the black camp, Pawns d6 and b6. And this will determine the outcome of this game. Now there will be a series of maneuvers on the white side. It is worth paying attention to black's actions. Nd4 Qc5 Nf1 Rc8 Ne3 Qa3 Bb2 Qc5 Qd2 g6 Ne2 Qg5 Red1 Bg7 Nc3 h5 Qe1 Rc6 Qf2 Qa5 Kh1 Qg5 Ne2 Rcc8 h4 Qc5 Bd4 Qc6 Qg3 Rb8 Bc3! Blacks, concentrating on defending weaknesses were shuddering in place. Their position did not change, they achieved nothing. White, on the other hand, regrouped their forces by positioning the optimal pieces for further action. Strategically, white had already obtained an almost winning position! 39... Nxe4?! RubChess decides to activate it's pieces by giving up Knight for two white Pawns, hoping for possible complications. fxe4 Qxe4 Bd2 Be5 Qf2 Nc5 Kg1 Bg7 Rf1 Rb7 a5 d5! Black rightly assumed that opening up the position even more increases their chances of a draw. White must play with precision. exd5 b5 RubiChess finally gets rid of the last weakness from the b6 square. Nf4 Bd4 Kh2 Rbe7 Black's concentration of forces at Knight e3 is gaining strength. Will it be enough to break the whites and reverse the fortunes of this game? d6! No! Why? Because... “pawns are the soul of this royal game...” 49... Rd7 Rbe1 Rxd6 Bb4 Rc6 Qf3 Qxf3 Rxf3 White led to forcible exchanges. There are no more Queens on the chessboard. The positional advantage will be converted into a decisive material advantage. 53... Nd7 Nfd5 Ne5 Rf4 Ba7 Rf6 Re6 Rxe6 Rxe6 Rc1 Bd4 Rc8+ Kh7 Nc2 Ng4+ Kg3 Be5+ Kf3 Bg7 Nf4 Re5 Ra8 Nh2+ Kg3 Ng4 Nh3 Bf6 Rxa6 1 : 0 ** Download game: Alexandria 7.1.1 vs RubiChess 20240817 With a one-figure advantage, Alexandria wins this skirmish. The key to victory turned out to be choosing the right strategy and then executing it. Alexandria succeeded by bringing about the creation of weaknesses in the enemy camp and then successfully exploring them. Game 2 - Time is... tempo! White: PlentyChess 3.0.2 Black: Integral 5 White's move. This time we have a game in which our considerations will already start from the middle :) The position is aligned. Each side has its chances. PlentyChess can already play 30.h4 actively, proposing a sharper confrontation, or opt for a calmer continuation - which is what happened: 30. Bc2 Ra5 Integral decides to strengthen focus on white Pawn a4. Nc3 Nc5 Qd1 Qd7 h4! A brave play, PlentyChess intends, declares the surrender of the white Pawn a4. Integral is faced with the dilemma of reinforcing the pressure on a4 and taking it in the end, or letting go and dealing with preparing to defend it's King's position ? 33... Raa8?! Could it be that “the threat proved stronger than its execution?” It looks like. Had Integral decided to consistently lead to taking white go Pawn a4 thus gaining a material advantage, the game could have gone like this: 33... Rfa8 34. h5 g5! 35. Qb1 h6 36. Nb5 Nxa4 37. Bf5 Qe7 38. Be6+ Kh8 39. Qg6 More than compensated the whites for the surrendered Pawn. Back in the game. Kh2 Qf7 Ne4 Ra5? Black feels confident enough to return to the idea of strengthening the pressure on the white Pawn a4. Except that at this level of players, this can already be considered a mistake due to loss of tempo. h5 gxh5 Ng3 Raa8 Returning the same Rook again is already an admission of error. Nf5 Qd7 g4 Rae8 Kg2 Rf6?! Another not so good move on the part of the blacks, this time the second Rook. Could it be that the blacks are disbelieving how much the whites have outsmarted them? ;) The correct one was: 40... Na5 41. Bxc5 dxc5 42. d6 Kh8 With white advantage but not yet lost. Ng3 hxg4 fxg4 Rf7 Again, black loss a tempo. Bf5 Qe7 Rh1 PlentyChess is preparing for the final assault. 44... Bf6 Nh5 Bg5 Rah3 Nd7 Ng3 Nf8 Rh5 e4 Be6 White disorganizes the defense of the black King. 49... Nxe6 dxe6 Rxf2+ Kxf2 Qf6+ Nf5 It is noteworthy that due to the loss of many tempos, black's Knight is stuck on the b7 field, which effectively deprived Integral of one figure and led to the current situation on the chessboard. 52... Nc5 Rxh7 Nxe6 Rh8+ Qxh8 Rxh8+ Kxh8 Qh1+ Kg8 Qxe4 Kf7 Qf3 Kg6 Qc6 Rf8 PlentyChess led to a winning position for itself. How to smash black's position completely in one move? Dear reader, you are traditionally invited to solve the chess puzzle. ...... .................. .................................... c5!! Yes! If you managed to find this move, congratulations :) 60... Nxc5 Qxc7 Rxf5 gxf5 Kxf5 Qxb6 1 : 0 Download game: PlentyChess 3.0.2 vs Integral 5 White with a beautiful maneuver crowned it's earlier gameplay by winning this exciting duel. PlentyChess took advantage of Integral's lack of strategic resolve to push its ideas and, as a result, turned the initiative it gained into an advantage that decided the outcome of the duel. Game 3 - Bad strategy bears withered fruit. White: RubiChess 20240817 Black: Caissa 1.21 White's move. What would you play in this position, dear reader? I don't know about you, but I certainly wouldn't play what RubiChess will do. b6? In my opinion, this is a fat strategic error. With one move, white deprives itself of any chance to play actively on the Queen's wing - where - after all - they concentrated their forces! And, although this is not apparent at “first glance” and it seems that white has not worsened their position, in practice they have deprived themselves of any chance for any progress on this side of the chessboard putting a question mark on the advisability of concentrating their heavy figures. A much more encompassing continuation was 23. bxa6 or 23. Qa2 23... Qd8 Of course, this move isn't a loser and RubiChess commanding the white sidelines is a real tough guy seasoned in battles with the best. The chess game will be a long one, so let's see how Caissa, will lead the game. 37... Rbd8 Here's what has happened over the past dozen or so moves: Caissa definitely improved his position by regrouping his forces from the Queen's wing where nothing threatened him. RubiChess. is trotting in place. a5 Here is an illustration of my last sentence.... 60... f5! Caissa, having set up its pieces optimally, proceeds to storm the white King's position. 70... f4 Unhurriedly but with determination! Qf1 This is how inconsistency and lack of initiative in action end. 78... fxg3 Black cracks the white Monarch's defenders. 85... Bxh4 Rg1 Bf2 Nxf2 Rxf2+ Qxf2 Qxf2+ Rxf2 Rxf2+ 0 : 1 Download game: RubiChess 20240817 vs Caissa 1.21 Caissa having three Pawns advantage easily wins. A wrongly chosen and executed strategy leads to inevitable failure. Game 4 - Reach where sight does not reach - beyond the event horizon White: Stockfish 17 Black: Clover 8.1 White's move. Here is the type of position that is often encountered after playing the Spanish opening. Both sides have the opportunity for rich figure play, where blow for blow is often exchanged. Black attacked the white Pawn a4. White can defend the Pawn by moving Bishop to the b5 square, but this may allow their opponent to completely equalize through exchanges. Example continuation: 22. Bb5 Nc5 23. Nxa5 Nbxa4 24. Nb7 Nxb7 25. Bxa4 Bxa4 26. Rxa4 d5! Back in the game. Bf4 Stockfish decides to give Pawn a4 hoping to gain the initiative. (Another, perhaps even more interesting continuation was 23. e5) 23... Bxa4 Clover decides to take Pawn a4, although watching this duel live, I saw that he spent a lot of time thinking about this move also considering a sharp continuation 23.... Nc5 leading to a surrender of quality (Rook for Bishop) for free play with one pawn more. Qg3 Bxb3 Bg5 The game is getting sharper. Stockfish likes it, it's his style. 25... Re7 If 25... Be7 then 26. Bxe7 with the threat of checkmate on g7 and the consequent loss of the black Queen. Bxb7 a4 Bd5 Nxd5 exd5 h6 Bf6 g6! Black defends the King's position very well. Clover withstands the pressure and calmly fends off the opponent's threats. Kh2 Kh7 Qf3 Kg8 Rxe7 Here is the defining moment in this game. Stockfish continues to play in its style. Any other move wouldn't have worsened white's position but also wouldn't have improved it. 32... Rxe7? The move, which would allow Clover to avoid defeat, is 32... Bxe7. From a purely human point of view, without deep analysis, it can be said that the blacks, at their own request, led to the binding of their own Rook and, in retrospect, to its exchange for the white Bishop On the other hand, engines see it differently from humans. Analyzing the positions before this move, equally Clover and also Stockfish saw exactly the same continuation moves up to a certain point, but Stockfish would choose 32.... Bxe7 and Clover chose as we already know 32.... Rxe7. The difference is that Clover choosing 32... Rxe7 he stated that by simplifying the position (exchanges) he was able to maintain the position and the draw at the cost of losing quality and having the material advantage of one Pawn. And Stockfish... He simply played "his game". As you will see dear reader, this game was more lost by Clover than won by Stockfish. Let's see how this game went on - at the most important moments. Re1 Qd7 Bxe7 Bxe7 Nf6+ Bxf6 Qxf6 Bxd5 The blacks' position on the surface looks favorable. However, their Bishop is weak compared to the white Rook, which, combined with the Queen, will soon show its effectiveness. h4 Kh7 Re7 Qc8 Ra7 a3 bxa3 bxa3 Rxa3 Having taken several black Pawns, Stockfish obtained the winning position. 41... Qg4 f3 Qe6 Qf4 Bb3 Ra6 Qe5 Qg3 Qf6 Rxd6 1 : 0 Although the game was still going on, it ended in an easy victory for Stockfish, which technically realized its material advantage Clover lost because it misjudged it's chances. As we can see, something like this happens even to the best chess engines. Of course, it is in the context of a chess event horizon estimated over the space of a dozen - a few dozen moves ahead. Download game: Stockfish 17 vs Clover 8.1 Summary Chess engines exceeding the 3700 CElo level in the MCERL rating achieve their dominance through a combination of immense computational power and strategic finesse. The analysis of games from the Chessengeria's Chess Engines Elite – 2024 tournament reveals that their success stems from the ability to exploit structural weaknesses, manage tempo, and execute strategies with precision. The key takeaway from these analyses is that victories at this level are not solely the result of brute computational force but also advanced positional understanding, creativity, and intuition—qualities that appear almost human. These elements elevate engine gameplay to an artistic level, offering profound insights into the evolution of chess as both a science and an art. What's next in 2025? What's next for the future? A fusion between the Stockfish project and the Lc0 project! Impossible? And this question will be answered in the next article :) * Diagrams created in the ChessX ** All games were prepared for download using Scid vs Mac  - free chess toolkit with extensive database, analysis and chess-playing features.

Your unique chess engine rating list - in the latest edition! MCERL 2024-09-09. Image generated by Darius using Microsoft Bing Image Creator I invite you to read the latest MCERL .

Changes at the beginning, middle and... at the end of the rating list ;) I invite you to read the latest MCERL .

Fruit is a chess engine that was created by Fabien Letouzey. Its first version, Fruit 1.0, was released in March 2004. It was one of the first open source engines, and its code was publicly available. In the middle of the first decade of the 21st century, Fruit became a reference and source of inspiration for many developers who created chess engines. Image generated by Darius using Microsoft Bing Image Creator Fruit's source code served as a base for developing other engines, from which innovations, optimizations, and ideas were drawn. This acted as a kind of “fruit planting”, where the Fruit code was the seed that gave rise and “development shot” to new or existing projects. In this way, many chess engines were created, some of which have achieved significant success in the world of computer chess. Like Rybka - who was stripped of all its titles... But about that in a moment. The power of Fruit's influence on computer chess since 2005 has been enormous! It all started in earnest with Fruit version 2.1 released in 2005. But before we get to that, it's worth noting that although earlier versions of Fruit were developed over a relatively short period of time (2004), its strength regularly grew significantly from version to version. Source: Fruit homepage, Computer Chess Club Archives In those days, the increase in strength of each successive version of the chess engine 10 or 20 Elo was a normal and approved thing. A 50 Elo increase in strength was a very big step forward, especially for the world's top chess engines. Fruit, on the other hand, in each successive version was stronger by about 100 Elo. And that was something special. Fruit was becoming more powerful. Fruit began to win over virtually every other chess engine including commercial giants such as, for example, multiple World Champion Shredder, award-winning Junior and Hiarcs, Sjeng, The King (ChessMaster), Gandalf. The free and respected Crafty, the ambitious Phalanx and many other non-commercial engines can also be included in the list of the defeated. What a free chess engine “from nowhere” created by one man is capable of is shown by the results of the 2005 World Computer Chess Championship held in Reykjavík. Source: CPW Fruit took an excellent second place by becoming the World Vice-Champion, ahead of all the strongest competitors, only second to the Zappa chess engine. Fruit was the only one to run on a computer equipped with a single CPU. All of its competitors played using multi-processor machines, such as Junior and Shredder using a 4-CPU. This fact further underscored the success Fruit had, beating its opponents with more computing resources. Open source - the seed of creativity. This could not go unnoticed. Like "mushrooms after the rain" strong chess engines appeared, which drew the best from Fruit's source code. At that time, the vast majority of chess engines were commercialized, only a few like Fruit and, for example, Crafty, Phalanx were free and their authors made the source codes available under the GPL license. What a surprise it must have been in the world of computer chess to see such a powerful chess engine emerge, with its author sharing his ideas, techniques and programming methods. And it works! Toga, Lion, Patriot, Strelka, Cyclone and so many other engines benefited from the fruits of Mr. Fabien Letouzey's work. In 2006, Fruit dominated the top of the rating lists. Mr. Fabien Letouzey worked intensively resulting in a leadimng position among the strongest. Source: Computer Chess Club Archives Subsequent versions got stronger and stronger. Fruit 2.2.1 took the top spot on the most respected SSDF chess engine rating list, clearly leaving behind such commercial giants as Shredder, Fritz, Junior as well as Gandalf, Pro Deo, Tiger and ChessMaster. Even Hiarcs had to acknowledge its superiority. The dimension of success for Fruit and its author was amazing. Fruit used new, innovative and effective programming techniques and methods. In addition, the C source code was written in an orderly manner and its structure was very clear. Do you know... That programmers and chess engine developers, although they had access to Fruit's source code, wondered on the computer chess forums what makes Fruit such a powerful chess engine? Surprisingly, experts in the field, although they understood the C language, understood the source code and had experience in developing chess engines, it was a big challenge for them to understand the ideas behind Fruit, which made Fruit so strong. Fruit is a chess engine that has been one of the most significant driving forces behind the development of the power and capabilities of a multitude of chess engines. Rybka controversy The strength and beauty of open-source software, among other things, is that anyone can use, enrich, improve - develop their project and also profit from it. The condition is to comply with the license provisions of the software in question, such as GPL 3. Unfortunately, not all authors of chess engines have respected this requirement. A negative example of this is the Rybka chess engine, whose author Vasik Rajlich was accused of violating the GPL by failing to disclose that he used Fruit source code in his chess engine. The GPL requires that any modifications made from GPL-licensed code must also be made publicly available under the terms of the same license. ****In December 2005, Mr. Vasik Rajlich gave an interview to Mr. Alexander Schmidt for uciengines.de, in which, among other things, he said, quote: "(...) I went through the Fruit 2.1 source code forwards and backwards and took many things." As a result of the investigations, *in June 2011, the ICGA (The International Computer Games Association) disqualified and banned Rybka and her programmer Vasik Rajlich from participating in previous and future World Computer Chess Championships. The ICGA has therefore decided as follows: Vasik Rajlich is hereby disqualified from the World Computer Chess Championships (WCCC) of 2006, 2007, 2008, 2009 and 2010. The 2nd-3rd place awarded to the program called “Rajlich” in the 2006 WCCC is hereby annulled, sole 2nd place is awarded to the program Shredder, and 3rd place in that event is awarded to the program Zappa. The 1st places and World Computer Chess Champion titles awarded to the program Rybka in the 2007, 2008, 2009 and 2010 WCCCs are hereby annulled, and all the other programs that competed in those events are moved up in the final tournament standings by one place. Thanks to its author, the Rybka chess engine was stripped of all its titles, was erased from the list of winners and its creator was covered in disgrace. As we can see from this example, violating the licensing rules of open-source software can lead to the most serious consequences. Unfortunately, this kind of licensing violation situation arose again after 2011, one of which I described in the article Fat Fritz 2 - free for all under the GNU GPL 3.0 license. And in this case, too, violations of licensing provisions related to the use of open-source software had consequences, this time in court. What you sow, you reap. Without going into the details of programming techniques, Fruit's source code contained breakthroughs, which is what allowed this engine to climb to heights in the world of computer chess and resulted in the inspiration for new powerful engines. Image generated by Darius using Microsoft Bing Image Creator Just how fertile were and are the ideas sown by Fruit in other chess engines, in clones and in subsequent versions of frut developed by other developers, can be seen in the CCRL rating list, which includes as many as 34 (!) fruits of the original ideas contained in Fruit 2.1. Source: CCRL - 2024-01-16 The strongest among them, Dark Toga 1.1, achieved 3207 Elo, as much as 515 Elo more than Fruit 2.1, with which it all began (according to the CCRL measurement scale). The new engines, which used Fruit's source code, were equipped with additional performance parameters and capabilities in addition to additional chess knowledge. For example, the Gambit Fruit features a sharp and uncompromising style of play, Toga III already uses a neural network, Dark Toga 1.1 can use multiple CPUs. The end of Fruit's development by Fabien Letouzey. Just 2 years after the release of Fruit 2.1, author Mr. Fabien Letouzey decided to end his involvement in Fruit development as lead programmer. As I have been following the history of the Fruit chess engine, I became sad when I found out about this. What a great pity and loss to the world of computer chess that such a beautiful and prolific mind stopped developing his work. It is only up to speculation how Fruit would be played today, what level it would have reached, how many more developers it would have inspired had its development continued. GNU Chess 6 In 2011, GNU Chess transitioned to version 6, which is based on Fabien Letouzey's Fruit 2.1 chess engine. This should certainly be considered a great honor, because GNU Chess is the open source chess engine of the Free Software Foundation. ***"(...) GNU Chess was initially written by Stuart Cracraft in the mid 80s, joined by John Stanback who contributed his own code to GNU Chess 2 and 3 which was laboriously and meticulously well-written. Dozens of developers have enhanced GNU Chess over the times. Version 5 was a complete rewrite by Chua Kong Sian, incorporating his chess program Cobalt and Cracraft's Gazebo. Fabien Letouzey is the primary author of GNU Chess 6, based on Fruit 2.1." GNU Chess is a project still under development today. As of the date of writing this article (January 2024), the current version is GNU Chess 6.2.9. 10 years after the release of Fruit 1.0 In 2014, exactly on March 17, which is 10 years since the publication of the first version of Fruit, Mr. Fabien Letouzey shared his new chess engine called Senpai 1.0 as a free chess engine under the GNU GPL 3 license. Senpai 1.0 is able to use multiple processors and is much more advanced than Fruit 2.1. It outperformed it by about 300 Elo (the version using 4-CPU) playing at 3050 Elo. In 2017, Senpai 2.0 came out, which was stronger by another 100 Elo which translated into a strength in the range of 3150 Elo. I would like to emphasize that Senpai 2.0 does not enjoy the benefits of a neural network. Let me guess that if Mr. Fabien Letouzey were still actively developing Fruit or Senpai, today we could enjoy a chess engine playing at least at the level of Stockfish or even higher. 2024 - 20 years after the release of Fruit 1.0 With full consciousness I wrote this article in 2024. Soon it will be exactly 20 years since a very important event in the world of computer chess, the appearance of Fruit 1.0. I am glad that in this modest way I can make my small contribution to the commemoration of this remarkable chess engine. Will a new and even more powerful engine, the fruit of the work of Mr. Fabien Letouzey, appear this time too in 2024 ? I hope so, and such hope I leave to you dear reader :) How strong is Fruit 2.1 today ? To determine this, I decided to compile the Fruit 2.1 source code in a contemporary development environment and give this engine a few thousand games a play. Fruit 2.1 used a MacBook Pro with an Apple Silicon M1 CPU. Source: MCERL (ongoing) 2723 Elo, is the playing strength of an engine created in 2005, an engine that at the time was winning over the strongest of its computer rivals. I will venture to speculate that Fruit 2.2.1 and its 2853 Elo and first place on the SSDF rating list in 2006, it's as if today (January 2024) the chess engine achieved about 3900 Elo in MCERL (Mac Chess Engines Rating List). As a reminder, the strongest development version of Stockfish from January 2024 achieves a score of 3850 Elo in the MCERL, in which several hundred chess engines participate. So let's see how Fruit 2.1 plays against modern computer opponents. Playing conditions same as in MCERL: 1 minute / game + 0.6 seconds / move Game #1 White; Fruit 2.1, MCERL: 2723 Elo Black: Carp 2.0, MCERL: 3132 Elo Carp, is a chess engine written in the Rust language. Its successive development deserves respect, which is reflected in the MCERL rating list, where five versions of it are playing: from one of the first Carp 1.1.0 (2287 Elo), to Carp 3.0.1 (3328 Elo). In this game, Fruit 2.1 is up against Carp 2.0.0 - the first version of this engine to use a neural network. 409 Elo difference in strength! How to win against a much stronger opponent? **Black's move. Carp with solid and balanced play has developed an advantage for itself on the chessboard. It leveled white's attacks and can look to the future with optimism, having a strong Pawns structure in the center. Unfortunately for it, the advantages gained were paid with a long time to think. Black had only 1 second left to complete the game. 34...Qa7?? A catastrophic mistake resulting from insufficient time to think. Dear reader, there is a tactical puzzle before you. I invite you to look for one move by white, after which black will be in a hopeless situation. ...... .................. .................................... 35.c5! Yes! If you managed to find this move, congratulations :) The white Pawn move wrecks black's position by exploiting a weakness on the g8 square - where checkmate threatens. 35...Rc4 Carp is forced to give up Rook for free to avoid immediate defeat. Other moves such as 35...Qa8 or 35...Qb8 also led to the loss of Rook through 36.Rxa4. 36.cxb6 36...Qb7 It sets a trap. 37.Rxc4! If Fruit had taken the black Rook 37.Qxc4? then after 37...c5+ there would have been an equalization of the position 38.Re4 d5! White gains a significant material advantage. The game ended with a victory for Fruit. As we have seen, it is possible to win against a much stronger opponent even with an inferior position. It is enough to lead to a situation that will create little time for thinking ;) This is how Fruit 2.1 won this game. Below this game prepared for download. Game #2 White; Counter 5.0, MCERL: 3015 Elo Black: Fruit 2.1, MCERL: 2723 Elo Counter is a valiant chess engine that has surprised me more than once when I watched it's duels within MCERL. It is one of the few chess engines written using Go language only and only because its author Mr. Vadim Chizhov stated that programming in C/C++ is not funny at all :) The use of a rather uncommon programming language such as Go did not prevent its author from creating a Counter playing with the power of more than 3000 Elo! White's move. The middle game. Both computer players play an interesting and sharp game looking for chances to gain an advantage on the opposite wings of the chessboard. Counter in order to seize the initiative did not hesitate to sacrifice Knight on the f5 square. Fruit, however, does not let himself be provoked by playing prudently. The position oscillates around equal with a very slight indication for black. 36.Bxe5?! Uncompromising! Counter wants to win! Fruit must be careful. The playing style of its opponent often resembles that of Grandmaster Mikhail Tal; it may not play the most accurate, but it only takes one mistake by the opponent to sweep it off the chessboard. 36...dxe5 Correct answer. If 36...gxf5 then 37.Qxf4 leads to a decisive advantage for white. 37.d6 Qb6 38.Rb1 Prevents black from infiltrating the white camp by moving the black Queen to the b2 square. 38...Nxc4! Strong play. Fruit does not give up the battlefield. 39.Bxc4 Bxf5! Blow for blow. Fruit is not worried about the potential loss of the black Queen, as it could then exploit with its Bishop the weakness of the e4 square and the exposed position of the white King. 40.exf5 The more defensive 40.Rb3 didn't change the situation significantly, example continuation: 40...Bxe4+ 41.f3 Rxh7+ 42.Nh2 Qxb3! 43.axb3 Bxf3+ 44.Rg2 Bxg2+ with a complete breakdown of the white King's position and an obvious win for black. Back in the game. 40...Rh7+ 41.Nh2 41...Qxb1 42.Bf1 If 42.Rxb1 then 42...Rxb1+ with checkmate. 42...Qb7+ 43.Bg2 43...Rxh2+!! The sacrifice must be accepted. 44.Kxh2 Qh7+ 45.Kg3 Ne2+! And again the hit, and how impressive. 46.Kf3 If Counter takes Knight 46.Qxe2 then 46...Qh4+ 47. Kf3 Qf4# 46...Nxg1+ Nothing can save the white King in this game anymore. 47.Ke4 Rb4+ 48.Ke5 Qg7+ 49.Kd5 Qf7+ 50.Kc6 Qb7+ 51.Kxc5 Qb5# Quite a successful demonstration of Fruit's capabilities, right? This is exactly how the Fruit 2.1 that defeated the strongest opponents in its time plays chess :) Below this game prepared for download. Game #3 White; Fruit 2.1, MCERL: 2723 Elo Black: Berserk 4, MCERL: 3086 Elo In the last game I will comment on, Fruit 2.1's opponent will be the chess engine Berserk 4. As Chessengeria readers may know, the Berserk engine is one of my favorites. Several years ago, Berserk charmed me with its style of play and its efficiency and ability to find unusual chess continuations. Today, on the day this article was published (January 2024), Berserk is the clear number two on the chess engine rating lists, just behind Stockfish. The fourth version of Berserk against which Fruit 2.1 will play was released in 2021. That is to say, Fruit 2.1 will be facing a "tough one" that was created 16 years later than it was! Let's go :) White's move. I would like to emphasize that this is the 28th move! Why? Well, Berserk is an enforcer when it comes to theoretically weaker chess engines. It's not uncommon for Berserk to end their lives before putting up 20 moves and in this game you don't see such a quick result ;) The position is equal. Figures of both sides occupy optimal positions. And white and black have some weaknesses: Pawns on d4 and d5 but can this be exploited somehow right now ? Yes, and this will be demonstrated by Fruit 2.1. 28.Ng6! Other possibilities were, for example, 28.Re3 or 28.Nf3, which, although more passive, objectively did not worsen white's position. Fruit chose the most promising and undoubtedly attractive continuation. 28...Bb4? An unforced error. It is likely that Berserk did not want to allow an equal, albeit uncomfortable, position to be forcibly created by 28...Nxg6 29.Qxd5+ Kh7 30.Qxd6 Qxa4 31.bxa6 bxa6 32.Rc7 White has one Pawn more, a Rook on the seventh line and a perfectly positioned Knight looking at squares f5 or h5. Although this position looks not so good for black, it is equal, because black can concentrate its forces on the f2 square near the white King and on top of that their two Rooks are perfectly positioned for a potential attack. Back in the game. 29.Nxf4 29...Bxc3 30.Nxd5! Berserk probably counted on 30.Qxd5+?! with the next 30...Rf7 31.Ng6 and equalizing positions 31...Rd8. Back in the game. 30...Bd2 Black wants to complicate the game. White must be on guard; every next move must be accurate. 31.Ne7++ Double check. 31...Kh8 32.Ng6+ Kh7 33.Nxf8+ Rxf8 34.Rc5 Ok, Fruit explained the situation. White has two more Pawns than black, which, with this arrangement of figures, should give them the win. Berserk did not want to lose easily. The game continued until the 90th move. Below are some selected situations from the rest of this skirmish. 38...bxa6 Fruit led to the removal of the Queens from the chessboard, which significantly helped it realize its advantage. 69.Nxh5 Move by move, slowly but gradually white's advantage grows. They already have three more Pawns. 82.Nxc7 The last hope of the blacks disappears, they lose the Bishop. 90.Rh7# The end. Wooow... When I first watched this game, the first thing I did was check to see if I was sure Berserk played black. At first I couldn't believe that Fruit gave Berserk such a lesson in humility! And yet it did :) Below this game prepared for download. The domain of Oldie Goldie chess engines is that they are capable of playing thrilling duels and winning even against much stronger opponents. Such a remarkable Oldie Goldie is Fruit, the beautiful fruit of the thoughts of the talented creator Mr. Fabien Letouzey, who is forever part of the passionate history of chess engines development. Image generated by Darius using Microsoft Bing Image Creator Dear reader, at this point there is nothing left for you to do but download Fruit 2.1 for your operating system and enjoy its gameplay :) Android – Compiled by Archimedes & Unknown Linux arm64 & x64 – Compiled by Darius Mac Apple Silicon & Intel – Compiled by Darius Windows – Compiled by Darius * Source: CPW ** Diagrams created in the ChessX. *** Source: CPW **** Source: CPW

For more than two decades, my chess memories have been intertwined with the presence of unique companions — the Phalanx chess engine. Phalanx chess engine - Oldie Goldie. Image generated by Darius using Microsoft Bing Image Creator This extraordinary experience began more than twenty years ago, when computer chess was still in its infancy. In those days, when the computing power of home computers was hundreds of times less than today's, Phalanx stood out with its unique style of play. It was a time when chess engines were just beginning to appear, and I myself sat down to play with one of the most unusual of them. Today, when chess technology has come so far that chess engines are capable of winning against any human, I recall with fondness those days when Phalanx XXII reached the 2100-2200 elo, which made him an attractive computer partner for me. In this Oldie Goldie article, I would like to share with you my long-standing relationship with Phalanx, a chess engine that managed to win a special place in my chess heart. I invite you to take a journey through the times when computer chess was on the eve of its heyday, and the Phalanx chess engine was my indispensable chess adventure companion. The author of the Phalanx chess engine is Mr. Dušan Dobeš, a Czech computer scientist and chess programmer. While student in the 90s, he created the Phalanx first versions, under the GPL. Mr. Dušan Dobeš was prolific Creator who released as many as twenty-two versions of Phalanx between 1997 and 2000. Phalanx chess engine rating on M1 CPU. Calculations made by Darius. Please take the calculations with a pinch of salt ;) In January 2000, when Phalanx XXII appeared, it was an amateur but advanced chess engine able to communicate via the command line and through the xboard protocol. And on top of that, its source code, thanks to the GNU (General Public License), was freely available to everyone, a rarity at the time, Phalanx, along with such popular and well-established open-source engines as Crafty and Fruit, was one of the most common chess engines bundled with all kinds of chess publications containing a CD. Also included in many Linux and FreeBSD distributions. At the height of its popularity, Phalanx XXII was honored by being included in a ChessBase product called Young Talents (only for Windows system). Young Talents by ChessBase. Original CD from 2000; poor quality. This was a CD release in 2000 and included the Fritz 6 GUI and seven chess engines playing different levels and styles of chess. In addition to Phalanx, the CD included the following chess engines: Anmon, Goliath Light, Gromit, Ikarus, Pazter and SOS. The addition of Phalanx XXII to a CD set called Young Talents by ChessBase proved to be a significant boost to the popularity of this unique chess engine. This release, which included Phalanx XXII, the Fritz 6 GUI and seven other engines with different difficulty levels, attracted the attention of a wide range of chess enthusiasts. With this step by ChessBase, the Phalanx XXII chess engine has gained new fans and contributed significantly to its recognition among young chess talents and experienced players. The introduction of Phalanx to various distributions of Linux and BSD-type operating systems also had a similar positive impact. The presence of Phalanx in these environments has made it possible for many new users from different platforms to enjoy playing with this remarkable chess engine *"(...) PhalanxXXII was the most interesting of the seven engines (in my opinion). I was looking forward to a wild sacrificial game against it (based on the engine's description at the ChessBase GmbH site), but Phalanx fooled me. I played a couple of games against it immediately after replaying a couple of Steinitz' games from Reti's book Masters of the Chessboard. Steinitz was the master of the pawn push. He often drove his pawns relentlessly forward to deny space to his opponent. To my surprise (I might even say "shock"), Phalanx does the same thing. Control of space is evidently given high priority in its evaluation algorithm. As I played against Phalanx, it seemed intent on throttling me ("python-like", to use the hoary old stereotype). I give this program high marks for positional play -- the pawn pushes it made were all strong ones, and it never gave my Knights a chance to exploit any holes it may have created. Despite the relatively low rating range in "Handicap and fun" mode (1150-1950), Phalanx was without question the most unique and interesting of the seven engines and I'm looking forward to my next game against it." It is worth noting that Phalanx and the other chess engines were adapted perfectly to work with the Fritz 6 interface, which was considered one of the most modern at the time. Analysis, engine tournaments (in which a human could also participate), chess mate searching, base handling… All this was available in cooperation with the above-mentioned engines at a level that could not be found in vain in the software of other developers. Fritz 6 GUI & Phalanx XXII Simple, clear, customizable and responsive interface! Once upon a time, ChessBase knew how to create the good product! Oh, how good and pleasant it was to use it :) And I used it. Dynamic, creative, sharp style of play at the level of a very strong club player. At the time, on my weak computer, Phalanx XXII was probably playing at the 2100 Elo level, which was within my reach, and sometimes, though rarely, I managed to beat it. Fritz 6 analyzing the entire game from 2003 between Darius the author of this article and Phalanx XXII That's when it sparked and computer chess became my passion. I realized that I could enjoy, comfortably, for entertainment, training, play and use chess software. And in my spare time, also watch the struggle of the engines. I'm not the only one who has noticed the impressive and even unique playing style of this chess engine. Scid vs. PC 4.13 & Phalanx XXIII Phalanx was and is included as one of the default engines for many Scid vs. PC / Mac versions, one of the most advanced chess database software. Scid vs. Mac 4.24 & Phalanx XXV After the release of Phalanx XXII in 2000, the author, Dušan Dobeš, ended active work on this chess engine, marking the end of official versions released by the developer. Chess community's contribution. In the meantime, the project was reactivated in 2006 by Mr. José de Paula Rodrigues, who made changes to the source code to, among other things, allow this engine to be compiled with newer compilers. Significant contributions to the popularization of Phalanx were also made by Mr. Jim Ablett, who prepared Phalanx for Windows, among other systems. And also Messrs. Pascal Georges and Steven Atkinson by including the Phalanx chess engine in the aforementioned Scid vs. PC/Mac software. The chess community has always been a place where enthusiasts from the community make invaluable contributions. In the case of Phalanx, it was Messrs. Jim Ablet, José de Paula Rodrigues, Pascal Georges and Steven Atkinson who made computer chess history by reactivating the project and making necessary changes. Thanks to their involvement, Phalanx continued to evolve, adapting to newer compilers and gaining new life on different operating systems and in the minds of many more users. October 2014 — as many as 14 years passed until Phalanx released the next version of XXIII. As in the late 1990s, this time too, the author Mr. Dušan Dobeš has released as many as three successive versions of Phalanx (XXIII, XXIV, XXV) in a relatively short period of time. Each has proven to be stronger, the latest version being Phalanx XXV published in May 2016, which according to the January 2024 MCERL (ongoing) plays at grandmaster level — 2629 Elo. This is a level pretty close to the strength of Fruit 2.1, one of the strongest and most famous open-source engines, which at one time dominated the first decade of the 21st century by beating its strongest rivals! Do you know... That Phalanx offers many customization options ? Among other things, the user can change its playing strength, choose different thinking time levels and search depth, also create an opening book based on the indicated games. As befits an engine dating back to the Oldie Goldie era, with Phalanx you can play using a terminal and typing in commands. All available options / parameters and commands are described by the author in the Readme file included with this chess engine. ***"(...) Current version (Phalanx XXII) plays risky, active chess and shows quite good tactical performance." So let's see what style Phalanx plays and what it can do :) For the first time in Chessengeria I will present a game played by a human against a chess engine. This game is from 2003 and was played in Fritz 6 GUI; the diagrams below come from this version. In 2003, after numerous skirmishes with Phalanx, I decided to seal our chess acquaintance with one epic game. Phalanx XXII was fearless to me, and I, with a determination worthy of a chess hero, took up the challenge. After many moves that kept me in suspense, Phalanx finally began to commit minor inaccuracies, probably the first since the beginning of our clashes! Phalanx fighting against the author of this article in 2003. Image generated by Darius using Microsoft Bing Image Creator I seized the opportunity, as if I had acquired a powerful weapon, and triumphed over Phalanx, powerful to me. I call it the 'Battle of the CheckMate' - the last move was as epic as the ending of the movie! ;) Game #1 White; Darius - this article author, Rating: about 2100 Elo Black: Phalanx XXII, Rating: about 2200 Elo, Pentium 200 MMX Playing conditions: 1 hour / game White's move. French defense, exchange variation. I chose an opening in which I made a long castling with the hope of interesting play on the King's wing. 12.dxc5 12...Nxc5 13.Bc2 Bd7 14.Qf1 Re6!? Typical Phalanx move :) Active, provocative with interesting prospects. Let's see what happens with this black Rook later in the game. 15.Nb3 I decided to develop my strength by strengthening my position. Attacking the black Rook e6 with 15.Nd4 or 15.Bf5 seemed premature to me. 15...Nce4 16.Bh4 Keeps tension. 16...Rc8 17. Kb1 Qc7 18.Nfd4 The d4 is a good square for the white Knight. Black will find it difficult to drive it out of this position. 18...Re5 Phalanx does not intend to return with its Rook to the rear. 19.f3 Rh5 20.fxe4 It is a better move than 20.Bxe4 Rxh4 21.Bf5 Rxh2 22.Bxd7 Qxd7 with a better position for black. 20...Rxh4 21.Nf5 Rf4 The h2 riser is "poisoned bait". If black had decided to take it via 21...Rxh2? this would have been followed by 22.Nxd6 Qxd6 and 23.e5 with the piece loss. 22.Qd3 Bf8 23.Ng3?! Also interesting was 23.Qg3 Bxf5 24.exf5 Bd6 25.Qd3 a6 26.h3 b5 27.g4= with a position in which white and black had a chance to attack on opposite wings of the chessboard. Back to the game. 23...Bg4 Good move. 24.Rd2 Nxe4 25.Nxe4 dxe4 26.Qe3= An equal position with a slight indication in favor of black due to the possibility of more open play. 26...f5?! A risky move, just so typical of Phalanx ;) Active, although it exposes the black King and limits the Bishop g4. This would be a good move in blitz, yet in this game both players were given as much as 1h each to think about. 27.Qxa7 White fearlessly takes Pawn a7. There is a slight white advantage on the chessboard. Due to the black Rook, which is stuck on the f4 square, black is unable to quickly organize an attack on the a-line towards the white King. 27...Be7 28.h3? Better was 28.g3. I didn't see that I could gain one Pawn more by 28...Rf3 29.Bd1 Rd3 30.Rxd3 exd3 31.Bxg4 fxg4 32.Qe3 Bf6 and 33.Qxd3 with a clear white advantage and a good chance to win. Back to the game. 28...Bh4!= Phalanx equalizes. A series of maneuvers from both sides follows. 29.Rg1 Bh5 30.Qe3 Bf7 31.Nd4 Bg5 32.Qe1 Qa5 33.Bb3 Bxb3 34.axb3 Can whites feel safe? 34...Ra8?! Yes! Black's move seemingly poses a threat to the white King, but it can feel safe, because the black Queen + Rook a8 tandem are unable to do anything without the support of their other figures; they cannot count on Rook f4, which is still "lost" occupying the f4 square. Undoubtedly stronger was 34...e3! and 35.Rd3 Re4 36.Qe2 f4 with the release of the black Rook and increasing pressure on the white position. Back to the game. 35.Kc2= At this point I felt that Phalanx in this game will not beat me :) 35...Rh4 36.Rd1 Bf6?! Stronger 36...g6 37.Qe2 Qa6 38.Qxa6 Rxa6 with good chances for draw. 37.Rf1 37...Rh5 38.Qf2 g6 39. Ra1 Qxa1 40.Rxa1 Rxa1 Black decided to exchange their Queen for two white Rooks. Will it help them, was it a good idea? In my opinion - no, because although there is material equality on the chessboard, their pieces are not coordinated. The two black Rooks occupy different positions and are not related to each other in interaction. The black Rook has been unable to find a good place for itself since the beginning of the game; this time it is stuck on the far square h5. 41.Ne6! A natural and strong move by white Knight. Black must finally start playing accurately and not just "actively". 41...Kf7 42.Qb6 Rh4 The lost black Rook tromps from square to square without effect. 43.Nf4 Rxf4 Black, seeing the helplessness of his heavy figure, makes the decision to give it up for the white Knight. 44.Qc7 Be7 45.Qxf4 Let's summarize what happened. After the reduction of material, slowly the game is moving towards the final phase. White has a good position with a clear advantage. Their Queen jets very operative and stronger than the uncooperative black Rook and Bishop. Three white Pawns stand on the Queen's wing against only one black Pawns, which bodes well for a decisive white advantage. 45...Rg1 46.Qf2 Rh1 Phalanx in this game is clearly having trouble rationally activating black Rooks. 47.b4 The parade of white Pawns is time to begin! 47...b5 Can one black Pawn stop a phalanx of white Pawns ? 48.c4!! No. And certainly not in this game. Perhaps this move does not deserve two exclamation points, however, for me, it was such a "glare" because it forces further favorable simplifications for white. Also good was 48.g4 Ke6 49.gxf5 gxf5 50.Qg2 48...bxc4 If 48...Bxb4 then 49.c5 Ba5 50.c6 with white winning. 49.b5 49...Bg5 50.Kc3 Rc1 51.Kb4 e3 52.Qe2 Blacks are in a difficult situation. They have to watch out for the sure-footed Pawn b5, which may be unstoppable in its advance in a moment. 52...Be7 53.Ka5 f4 54.b6 Bd6 55.Kb5 Also leading to the win was 55.b7. 55...Ke6 56.Kc6 Bb8 57.Kb7 Also winning was 57.Qg4+ Kf6 58.Kd5! although somewhat at odds with the strategy I adopted of supporting the white King in the advance of Pawn. 57...Be5 58.Kc8 Ke7 59.b7 White's win already close. They must watch out for the tactical traps that Phalanx likes to set. 59...c3 60.b3 c2 61.b8Q Blacks must give up their Bishop for a new white Queen. It appears that Phalanx must accept its defeat in this chess game. 61...Bxb8 62.Kxb8 Phalanx did not surrender this game until move 76. Before that, I led another white Pawn to the b7 square near the promotion position, not allowing black to get any counterplay. 76.Qe2 1 - 0 Dear reader, if you made it to this point, I salute you :) It was a long game, in which I tried to show Phalanx's style of play against the man. Why did Phalanx lose when it did not make a clear fat mistake? The answer is: man good management of the relatively long time to think (1h), strategy and its determined execution without getting into a tactical brawl with the chess engine. By the method of small and successive steps at my then level of chess playing, I managed to lead Phalanx to a gradual deterioration of its position and eventually to its surrender. Below this game prepared for download. Phalanx often - not only in this game - tries to play actively, creatively and interestingly. And it does not always make the strongest moves. Although they are always difficult, provocative, thought-provoking moves. And that's what I like this chess engine for. It is always a challenge to play with it :) Does Phalanx play against other chess engines in the same style ? Let's check it out. All of the following games were played under conditions same as in MCERL: 1 minute / game + 0.6 seconds / move Game #2 White; Akimbo 0.4.1, MCERL: 2911 Elo Black: Phalanx XXIII, MCERL: 2509 Elo Akimbo is a chess engine written in the Rust language that evolved from the Kimbo engine. Kimbo and Akimbo are both participants in MCERL games, and I am happy to write that the author of these chess engines Mr. Jamie Whiting is doing a great job. One of the first versions Kimbo 0.2.1 reached 2385 Elo in MCERL, while the latest version Akimbo 0.8.0 plays at a very high level of 3551 Elo! Akimbo 0.4.1 is one of the next consistently developed versions, and in this incarnation it is stronger than Phalanx XXIII by as much as 402 Elo. **Black's move. Dear reader, you are traditionally invited to solve the chess puzzle. You will probably rightly guess that Phalanx has taken advantage of its tactical capabilities in this position. So, look for a quick solution ...... .................. .................................... 34...Rxf2!! If you managed to find this move, congratulations :) Phalanx at the cost of Rook removes an important point of the white King's defense - Pawn f2. The sacrifice must be accepted, threatens checkmate on the h2 square. 35. Kxf2 25...Qh2+ 26.Ke3 Nothing changes 26.Kf1 Rf8+ 27.Qf7+ Rxf7 with a quick end for white 26...Ne5! It leads to checkmate the white King. 27.b3 Qg2 28.Bxe4 d4+! 29.cxd4 cxd4+ 30.Kf4 Qh2+ 31.Kf5 g6+ 32.Qxg6+ hxg6# Beautiful checkmate! Phalanx XXIII - the chess engine from 2014 - wins in a very nice way against a much stronger opponent :) Below this game prepared for download. Game #3 White: Phalanx XXV, MCERL: 2629 Elo Black; Diablo 0.5.1, MCERL: 2466 Elo Diablo is a chess engine that is 19 years old on the day this article was written. It presents the level of a strong champion and it is a pity that it is no longer a chess engine under development. It is noteworthy that its author Mr. Marcus Prewarski has made the Diablo source code available under the GNU GPL license - it is available to anyone interested. Another example, and this time rather short to show the characteristics of Pahalanx's style of play. White's move. The beginning of the game. Phalanx is only nine moves ahead. The position originated in the opening of Ragozin and is one of the more frequently chosen by human and computer players. Usually at this point it is chosen: 9.cxd5 / 9.a3 / 9.Rc1 Phalanx played 9.Rg1 What a typical move for this chess engine. Phalanx signals: if you do a short castling, expect an attack along the g-line. There is no room for speculation here, Phalanx always offers a sharp chess move. And if you go to confront it, I will "thunder from the sky" ;) 21.Qb6 In the meantime, there have been several moves. Diablo made a short castling and Pahalanx opened the g-line. The position is equal. 21...Ra6?? The balance was maintained, for example, by 21...Bc5 22.Qc7 Bd6 23.Qb6 Bc5 with moves repeated. 22.Qd4 22...Bxh2 23.dxe6 fxe6 24.Bh7+ Kf8 25.Bg6 It sets a net from which the blacks will not disentangle themselves. 25...e5 26.Qh4 Bf5+ 27.e4! 27...Rxd1 If 27...Bxg6 then 28.Qh8# 28.Rxd1 Bxe4 29. Ncxe4 Qe6 30.Nh7+ 30...Kg8 31.Qd8+ Qe8 32.Qxe8# This example shows that Diablo only once underestimated Phalanx's attack capabilities, which quickly led to its defeat. Below this game prepared for download. Game #4 White: Phalanx XXV, MCERL: 2629 Elo Black; Rodent IV 0.33 (Tal), MCERL: 2786 Elo "The madman met... madman" ;) Phalanx is embracing chess madness. Image generated by Darius using Microsoft Bing Image Creator In the last example, I will present a game in which two of its participants, determined to attack and willing to provoke and sacrifice, make a mutual confrontation. Let's see what will result from this on the chessboard! Rodent is a highly customizable chess engine that allows you to create and play against so-called personalities. I reviewed this chess engine in the article Final Rodent - Review / Config. / Download In short: a Rodent engine with Tal's personality plays with style reminiscent of World Champion MIchail Tal. This usually means impressive though not always precise chess, which is often very challenging for opponents playing at similar and lower levels. Black's move. The position was created after white's 13th move in the Spanish game, Chigorin's closed variant. The game in this variant is usually characterized by a lot of maneuvering on both sides, looking for weaknesses and trying to create a positional advantage. Usually, yes... But not for Rodent with Tal's personality :) 13...Qc8?! Black "on a good day" takes on the white Pawn h3 and such a move for this engine means a desire to destroy this Pawn, which is one of the defenders of the White King. 14.d4 A natural move for white. Increases the tension in the center and creates a potential space for exchanges and the opening of the c-line, at the end of which the black Queen was found. 14...exd4 15.cxd4 Nc6 16.Rc1 Exactly right! 16...c4 Blacks do not want to open c-line. 17.Bb1 Bd8 Objectively, it was better to depart with the Queen from under the fire of the white Rook c1, for example to the b7 or d8 square. But... it would have been inconsistent with Rodent-Tal's intentions ;) 18.b3! 18...Bxh3?! "Crazily" but quite spectacularly. Blacks do not "want to compromise" their previously devised plan. Black's Pawn c4 defense would be doomed to failure, and more importantly it would be passive - which is totally out of Tal's personality style. 19.gxh3 Qxh3 20.bxc4 Phalanx is also consistent in its approach. 20...Ng4 21.cxb5 Nb4 Even sharper would be 21...Re6 22.Bf4 Re6! 23.Nf1! Just in time. Knight supports white King's defense forces. 23...Rf6 24.Bg3 Rh6 25.N3h2 This is what Knight was put on the f1 square for. 25...Nxf2! Blacks put everything on one card - to smash the white defense regardless of their own losses. 26.Kxf2 Rf6+ 27.Kg1 h5! 28.e5! White is not going to look passively at the development of the situation. Pawn's move to the e5 square opens up the position and gives more room to maneuver with white's Bishop looking menacingly toward black's King. 28...dxe5 29.a3 axb5! 30.axb4! Ra3 Bravely. Rodent-Tal first sacrificed another piece - Knight b4 in order to bring another of his heavy pieces into play. 31.Bxe5 Rfa6 32.Bd6 g6 33.Re8+! Phalanx begins to grind the position of the black King with the Rook + Bishop mill. 33...Kg7 34.Bf8+ Kg8 35.Be7+ Kg7 36.Rxd8 The whites have "only" four more light pieces ;) Rodent-Tal by no means intends to give up. 36...Re6 37.Bf8+ Kh7 38.Qd2 Creates threats of checkmate (Qh6 and Qg7#). 38...Ree3 39.Re8! 39...Qh4 40.Nxe3 Qg5+ 41.Neg4! 41...Rg3+ If 41...Qxd2 then a very nice checkmate follows 42.Nf6+ Kh8 43.Bh6# Back to the game. 42.Kh1 Qd5+ 43.Be4 43...Qxe4+ 44.Rxe4 g5 45.Qxg5 45...Rxg4 46.Nxg4 hxg4 47.Qg7# Here's what happens when two computer "chess madmen" meet at the chessboard ;) In this, the latest example, we could see that Phalanx, while playing hard and uncompromisingly itself, is able to get a favorable result by playing focused, with an opponent theoretically stronger than it and with a similar style of play. Below this game prepared for download. You are not doomed to failure with Phalanx chess engine... Phalanx and its phalanx. Image generated by Darius using Microsoft Bing Image Creator ...albeit Phalanx and its phalanx can really give you a hard time during the game. I want to play with good old Phalanx. How to do it today? This question is as legitimate as possible. Phalanx XXII was, after all, released in 2000, 24 years ago as of the date of writing this article. This is even in the world of computer chess a true prehistory. The user can choose the command line to directly communicate with this chess engine, but today, playing with the chess engine via this method (CMD on Windows, Terminal on Linux and macOS) should be considered a curiosity rather than a convenient way to use the chess engine. Phalanx XXII and its earlier versions communicate via the Xboard version 1 protocol. Unfortunately, most GUIs either do not support this old protocol or do so incorrectly. Phalanx XXIII and its newer versions communicate via the Xboard version 2 protocol. The Phalanx chess engine does not support the UCI communication protocol. Thus, it is not possible to run this chess engine in, for example, ChessBase, Hiarcs Chess Explorer (Pro) or any other program supporting only UCI engines. You can use the Wb2Uci adapter, although I do not recommend this solution - this engine does not always work well then. If you want to play with Phalanx XXII, and... 1. You have access to the Young Talents release (only for Windows). Then I strong recommend doing so through the Fritz 6 interface, which is available in the Young Talents edition from ChessBase. Unfortunately, it is very difficult to acquire a CD of this edition nowadays. From time to time you can find them on ebay.de / ebay.com, for example. If you already are or will be the lucky owner of this release, you can use the Phalanx XXII engine in a much newer edition of the Fritz program, which supports engines from Young Talents. According to my tests, Fritz 15 in the 32 bit version is probably the last GUI that fully supports Phalanx XII from the Young Talents release; it is a much newer GUI than Fritz 6 with great capabilities that allows you to take full advantage of Phalanx XII in a Windows environment. Fritz 15 GUI (32-bit) & Pahlanx XXII (Windows) 2. You do not have access to the Young Talents release. First, download Phalanx chess engine for the operating system on which you intend to use it. You'll find the ready-to-download engine at the bottom of this article. This suggests you use: Xboard program, which is for Linux and Mac Winboard program for Windows Both of these programs are downloadable from the Files section. Xboard 4.9.1 GUI & Phalanx XXII (Mac) Arena program, which is for Linux and Windows Arena 3.10 beta GUI & Phalanx XXII (Linux) Aquarium for Windows Aquarium 2017 GUI & Phalanx XXII (Windows) If you want to play with Phalanx XXIII or greater That, too, you can use the GUI mentioned above in point 2. In addition, a good choice would be Banksia GUI, which perfectly supports chess engines that communicate via Xboard protocol version 2. Banksia GUI is available for Linux, Mac and Windows. Banksia GUI 0.58 (rc1) & Phalanx XXIII Users of Android smartphones and tablets can take advantage of the excellent Chess for Android program. Chess for Android 6.8.6 & Phalanx XXIII To sum up this lengthy article... Although the Phalanx chess engine did not reach the level of the strongest computer players, its analyses continue to offer a unique and valuable source of ideas and concepts. In my opinion, having dealt with several hundred chess engines, Phalanx takes the top spot on the podium in the category of chess engines with the most human-like playing style. The Phalanx chess engine has the ability to surprise with interesting strategies, inspiring enthusiasts of our noble game. If you've ever faced the Phalanx chess engine, share your memories! Interesting moves, difficult moments - I would love to read about your experiences. Warmly welcome you to the comment section. I invite you to download Phalanx XXII - the version that has received so much acclaim around the world. Linux arm64 & x64 – Compiled by Darius Mac Apple Silicon & Intel – Compiled by Darius Windows x32 – Compiled by Steven Atkinson Note for Windows users: If you will want to use Phalanx in a GUI that supports only the UCI protocol (e.g. ChessBase, Hiarcs Chess Explorer (Pro)), you can try using an adapter by Odd Gunnar Malin called Wb2Uci (Winboard to UCI) for this purpose. Unfortunately, the operations of this engine via an adapter are not always correct. You can download it via the Files section (Tools folder). Android – Compiled by Archimedes & Jim Ablett I recommend downloading the latest compilation from Archimedes, which was created in 2024. It works on older Android devices and also on the latest ones (in the archive, look for the OEX folder). Jim Ablett's compilation was created to run on the oldest Android devices; if you have one - go ahead and download it. I received it courtesy of user tmokonen from the talkchess forum. Tony, thank you very much :) * chessbase.com, May 28th, 2000 ** Diagrams created in the ChessX *** Juergen Haas, About.com

Surprises and a new trend among chess engine authors. I invite you to read the latest MCERL.

It's already the 10th version of this chess engine, and it hasn't been mentioned on Chessengeria yet… Image generated by Darius using Microsoft Bing Image Creator 3648 Elo on the CCRL scale (1 CPU) is an amazing result for an engine that has been in development since April 2023, a mere 9 months! (as of January 2024) Source: CCRL 2024-01-19 Obsidian is released as an open-source chess engine under the GNU GPL 3 license. Its author is gabe, who publishes his work on GitHub. Although Obsidian in the current version uses and also in earlier versions used a neural network, considering that the first version debuted with 3003 Elo and today we have more than 600 Elo more, this must be impressive. Here's what the author wrote for Obsidian's 10th edition. " This update brings quite large Elo gains, but also important bug fixes (such as taking a tiny amount of CPU while not searching). The neural network is the same, and the improvements are only about search and performance. Regarding usability, Obsidian finally supports being executed on hardware where pext is unavailable or slow (Ryzen 3...) Elo difference: Obsidian 10.0 vs Obsidian 9.0 (STC) Elo | 53.07 +- 6.69 (95%) Conf | 10.0+0.1s Threads=1 Hash=16MB Games | N: 5008 W: 1588 L: 829 D: 2591 Penta | [6, 306, 1165, 977, 50] Obsidian 10.0 vs Obsidian 9.0 (LTC) Elo | 56.96 +- 10.43 (95%) Conf | 40.0+0.4s Threads=1 Hash=64MB Games | N: 2000 W: 630 L: 305 D: 1065 Penta | [1, 93, 496, 400, 10] " If, according to the author, the increase in strength of about 50 Elo at this level is due only to the fixes bugs, then I dread to think what strength Obsidian 11 will play with ;) Just a few years ago, before the introduction of neural networks into the world of computer chess… If I had seen a chess engine starting at 3000 Elo and after less than a year having 3600 Elo on the counter, I would not have believed that this was the result of independent work. However, on the day Obsidian 10 was released, that is January 2024, we are in a different era of computer chess. Today, the most powerful chess engines use neural networks and open their sources to the world. And that's what open source is all about: sharing, developing, inspiring. Which is most likely evidenced by the Obsidian chess engine right now :) Heartfelt congratulations to gabe, whose chess engine ruthlessly broke into the top of the strongest! So let's see how Obsidian 10 performs against opponents playing at the very high level. Playing conditions same as in MCERL: 1 minute / game + 0.6 seconds / move Platform: PC, Intel Core i5 (Haswell), Windows 10 Pro, Banksia GUI. Game #1 White: Obsidian 10, MCERL: Elo not measured Black: Viridithas 11, MCERL: 3537 Elo Viridithas is one of the strongest chess engine written in the Rust language on the planet Earth. It has played more than 2700 games in the MCERL cycle, confirming its class. But even to it, such slip-ups happen... Black's move. An equal position in which white holds the initiative. Viridithas should first and foremost defend its King. 34...Re4?? Better 34...Be4 and 35.Rfg4 Ree7= with equal chances. 35.Rf8+ White immediately seizes the opportunity to penetrate the eighth line, where the black King is. 35...Kh7 Dear reader, in this position you can give chess mate in few moves! Would you like to try to point out the first of these moves, leading to a forcing win? ...... .................. .................................... 36.Rxg7+!! If you managed to find this move, congratulations :) 36...Rxg7 37.Rh8+! Obsidian sacrifices the second Rook. 37...Kxh8 If 37...Kg6 then 38.Qf6# 38.Qf8+ Kh7 39. Qxg7# Objectively looking at the course of this game, it was more this game that Viridithas lost than Obsidian won ;) Nevertheless, a nice win, right? Below this game prepared for download. Game #2 White: Obsidian 10, MCERL: Elo not measured Black: RubiChess 20240112, MCERL: 3709 Elo RubiChess, is an early 2024 fighter in the super heavyweight club. It is able to beat anyone, and has proven it thousands of times. Black move. RubiChess has built up an advantage on the Queen's wing. It activated the figures and boldly put Pawns forward. Obsidian, on the other hand, has a strong point in the form of Pawn e6 and the potential for action on the King's wing. 26...cxb3 Good move. Black takes the weak Pawn b3 with a parallel attack on the white Rook f1. 27.axb3!? Bravely. Obsidian decided that it was better to give up Rook for a strong black Bishop than to play a passive game with an advantageous opponent. If 27.Rg1 then 27...bxa2 28.Qxa2 Bc4 29.Qb2 Qb5 with white probably losing. Back to the game. 27...Bxf1 28.Qxf1 Several maneuvers that fit into the logic of the game of both sides follow. RubiChess wants to take the weak white Pawn b3, Obsidian meanwhile hopes to revive its forces. 28...Qd6 29.Bb2 Nxb3 30.Bxd5 Nc5 31.Qf3 Comparing the current situation on the chessboard to the situation that would arise after the preservation of the white Rook (27.Rg1), white is better off. They are playing freely on the white squares and, except for Knight, have managed to activate all the figures. 31...a5?! Blacks manifest their self-confidence. Slightly better was 31...Red8 with positioning of Black's Rook and enhanced action on the d-line. 32.Ng2 Before the black Pawns on the wing begin to pose a serious threat, Obsidian activates its Knight. 32...Qb8? Black self-confidence continued. Unfortunately for them, it was a weak move, after which black's advantage disappears. Probably RubiChess intends to press on the Queen's wing, when meanwhile the last two moves allow Obsidian to take a deadly initiative. 33.Nf4 33...Na4? It was worth trying 33...Rcd8 The Blacks are playing as if they don't see what's happening on the opposite King's wing, or.... as if they didn't prove that the "freshman" Obsidian could do something to them ;) 34.Qg4! White sacrifices Bishop b2, pushing for the enemy King's position. 34...Nxb2 35.Nh5 The threat of checkmate on the g7 square appears. Black's position is impossible to defend. 35...g6 If 35...Bf8 then 36.e7+ Kh8 37.exf8Q+ Rxf8 38.Qg7# 36.fxg6 36...h6 A hopeless situation. As a result of overestimating their own capabilities and making wrong decisions early on, black can only watch. The finale of this skirmish is approaching. 37.g7 37...Rc1 At the price of a Rook, black “momentarily” dismisses the moment of defeat. 38.Rxc1 Qe5 39.Qg6 Qxd5+ 40.e4 Qxe4+ 41.Qxe4 In a few moves the black King will be checkmated. 41...Nc4 42.Rxc4 Bc5 43.Nf6+ Kxg7 44.Nxe8+ Kf8 45.Qg6 Ke7 46.Qf7+ Kd8 47.Qd7# Bravo Obsidian! It found itself in a difficult situation against a strong computer player from the top, did not lose its resonance and won nicely. Below this game prepared for download. It plays well, this "newcomer" Obsidian 10. Too bad it won't play for all chess engine enthusiasts. Unfortunately, the source code is written in such a way that it does not support compilation of this engine for Macs with Apple Silicon and Intel CPUs. Compilation for machines using Linux and ARM CPUs was also a failure. I have not found on the Internet a compilation of this engine for devices using Android. Nowadays, there are fewer and fewer chess engines that are only written for one or two operating systems. Typically, authors are keen to make their work available to the widest possible audience. This is also the mission of the Chessengeria blog, to promote, popularize and disseminate computer chess. I hope that in future versions of his excellent Obsidian, gabe will enable to use his engine not only on the Windows platform but also on Android, Linux, and Mac :) I encourage you to download and check out the Obsidian chess engine. Linux x64 – Compiled by Darius Mac Intel x64 – Compiled by Darius Unfortunately, I have not been able to compile a newer version of Obsidian than Obsidian 7 for Macs with Intel CPUs. Windows x64 – Compiled by Darius * Diagrams created in the ChessX.