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Phalanx - Oldie Goldie

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.


Darius_vs_Phalanx-XXII
.zip
Download ZIP • 1KB


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.


Akimbo-0.4.1_vs_Phalanx-XXIII
.zip
Download ZIP • 1KB


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.


Phalanx-XXV_vs_Diablo-0.5.1
.zip
Download ZIP • 1KB


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