[Coladam] About Coleco chess programs

Daniel Bienvenu newcoleco at yahoo.fr
Sun Jul 25 07:55:39 CEST 2010

Last time, during the chat session, I was asking about chess programs for the Coleco and Modem chess was mentioned as the better chess program for the Coleco Adam computer. There is at least 3 chess programs for the Adam, and I hope to see a chess program for the ColecoVision game system, as it was supposed to be (ColecoVision silver catalog), in order to at least show that the console can also play chess.

Based on the ColecoVision silver catalog, Fidelity Chess Challenger was proposed. Compared to Sargon and other chess programs of that time like Boris and microchess, Chess Challenger offer a decent chess challenge for chess players, with an average of 2 minutes per move.

Boris : http://www.boris-is-king.com/homepage.htm
Microchess : http://www.benlo.com/microchess/microchess.html
Sargon : http://web.archive.org/web/20070614114334/http://madscientistroom.org/chm/Sargon.html

The following web site about various Chess Challenger devices gives me a clue about what the ColecoVision version may be based on. The model CC10 (for Chess Challenger 10) need 0.5KB of RAM and 4KB of ROM (includes 100 opening moves), which is within the limits of the ColecoVision game system. And, the next model, with voice, seems to use too much RAM to consider being used for the ColecoVision, 1KB of RAM (which is total RAM size in the console) and 8KB of ROM (includes 500 opening moves).


Considering the ranking of a novice chess player to be just above 1000 Elo, a chess program like CC10 is evaluated around 1300 Elo. Microchess is faster but also gets a lower rank. So, it's enough for a pretty decent challenge.

After seeing the small size of the small RAM size needed and the openings library of these chess programs, the major problem is the time response, which depends on the algorithm used to evaluate the possible moves (like a game-decision tree analysis). There are a lot of different strategies and brute force is the slowest one.

So, what could be a chess game for the ColecoVision game system?

For fun, I was thinking of a way to build a nice openings library. So far, I think I can fit about 512 moves in 16KB, maybe 3 times more with luck and compression. So far, I find out these web pages that can help to decide what should be in the openings library.

How to beat a chess program (should help to increase the Elo ranking)

GameKnot database (results of thousands of chess games played at this web site)

Openings stats (gives advices about what to play)

According to the last website, even if "1. e4 e5" is very popular, the best opening should be "1. c4 c5". So, I've started with this opening and I've typed a list of at least 150 interesting variations after "1. c4 c5" , with the help of the gameknot database, to be in the openings library of a potential ColecoVision chess program. I suppose I'll have to limit my enthousiast if I want the openings library to fit in a 32KB chess game project.

I've absolutely no idea on how to code the chess engine itself to make it run just fine, even with all the documentations here and there about how to code a chess program, but a good openings library should help to start quickly and nicely each chess match. 

Other links :

Easy to read chess program listing
TSCP : http://www.tckerrigan.com/Chess/TSCP

Impossible to read source code tiny chess games
Toledo Chess : http://nanochess.110mb.com/chess1.html
Micro-max : http://home.hccnet.nl/h.g.muller/max-src2.html


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