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4ku 2.0 - released.

Less than 4KB and a strength over 2700 Elo - this is chess engine 4ku.

This remarkable feat was accomplished by kz04px, who is the author of the 4ku engine that plays at the level of a top grandmaster.

4ku is an open source free chess engine under the MIT license.

Those who are at least somewhat familiar with computer chess know, that there are engines that are stronger than 4ku, but much larger.

Stockfish 15.1, for example, takes up 613 times more volume than 4ku 2.0.

4ku, it's actually one chess engine, but it can come in two versions.

  • The first is the standard version, which takes up tens of kilobytes (which is very little),

  • And the second version is the so-called mini, which takes up less than 4KB. The 4ku-2.0 mini version is only available for Linux. I hope this will change in the future and there will be a mini version that runs on Mac and Windows.

It is worth mentioning that 4ku-mini played in the TCEC's S24 Swiss 4 tournament.

And it also played in MCERL where after 506 games, chess engine 4ku 2.0 standard version reached a rating of 2789 Elo.

Source: MCERL (ongoing)

At such a small size of a few tens of kilobytes, impressive!

This means that 4ku can run on any computer as long as it is properly prepared for it and... will play with quite a bit of strength!

I really like the idea of creating strong chess engines with the smallest possible size. Perhaps there will be content related to this topic on the blog in the future.

Feel free to visit the download area.

Android – Compiled by Archimedes

Download 7Z • 682KB

Linux arm64 & x64 – Compiled by Darius

Download 7Z • 273KB
Download 7Z • 273KB

Mac Apple Silicon & Intel – Compiled by Darius

Download 7Z • 267KB
Download 7Z • 270KB

Windows x64 – Compiled by Darius

Download 7Z • 721KB


In the Files area you will find free chess engines for download.



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