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CT-800 dedicated chess computer running open source software.

Updated: Mar 15

The author of the CT800 computer and chess engine is Mr. Rasmus Althoff, a German programmer and chess enthusiast. His project was published in 2016 and is constantly being developed.

Source: CT800 Homepage

This project is licensed under the GNU General Public License version 3.

The CT800 chess computer has a built-in LCD display and a keyboard for entering moves. The computer has many modes e.g. play, analysis, mate solver and time controls. The computer can also save/load games and play them back later.

Source: CT800 Homepage

You can't buy it, but you can build it yourself thanks to extensive documentation.

Documentation of the CT800 computer and engine is available on the developer's website.

You can find the following information there:

  • The CT800 chess computer manual in PDF format, which describes its functions, how to use it, software updates and troubleshooting.

  • A wiring diagram and parts list of the CT800 chess computer, which you need to build your own copy.

  • Binary files and source code for the CT800 chess engine.

The project is superbly documented.

In addition to schematics, source codes, etc., it also contains an excellent user manual, which, like all other documents of this project, is user-oriented.

Document: manual-ct800.pdf

Document: auxboard.pdf

The CT800 chess engine in its latest version 1.44 is based on an alpha-beta algorithm with many improvements. On dedicated computer it plays around 2100-2200 Elo with the strength of a chess expert.

On my MacBook, it presents grandmaster strength: 2607 Elo, meaning it is a worthy opponent and playing / training partner even for discerning chess players.

Source: MCERL (ongoing)

CT800 chess engine has versions for popular operating systems such as Windows, Linux, Mac, Raspberry-Pi, Android.

Because of its support for the UCI protocol, the CT800 chess engine allows you to enjoy its unique style of play on popular applications and chess GUIs.

So let's take a look at how the CT800 chess engine handles challenging opponents.


First opponent: Deep Junior playing with black.

Junior is a real tough "guy"; one of the toughest computer players. Brave, precise, not shying away from complications.

Although nowadays, it can't compare with the strongest, because it hasn't been developed for many years. In its time, it was Junior who was one of the few who got the chance to play a match with Garry Kasparov – one of the best human chess players of all time.

Who does not remember Junior's beautiful sacrifice (Bxh2+!!) in one of the games with G.Kasparov. Junior is a great chess engine and multiple Computer World Champion.

White was in command of the CT800 having just Junior against him, an opponent of such a great class of opponent.

The following position, is one of the typical ones in which Junior crushed his opponents: two black Bishops having a lot of space, a Queen and... an unstoppable desire to attack the white King.

The 33rd white move, what did CT800 do ?

It did not move to the defense. Oh no!

It played a beautiful 33.c5! sacrificing a pawn and bringing its Queen into play.