About E.T.Chess

A chess program by Eric TRIKI


Start E.T.Chess : double-click on et_chess.bat

Make the menu appear : just right-click.

Take-back : select REVISE CURRENT GAME in the menu, a window composed of a tiny chess board and the move list appears. Select one of the moves, click : in the tiny chess board appears the position before this move was made, click another time : the game restarts in the selected position.

Castling : click on the king and then on the destination square, the rook moves automatically


The program's level is set with the STRATEGY and TACTIC options of the menu.

* STRATEGY sets the positional strength of the program.

* TACTIC sets the combinatory strength of the program.

To simplify let's say that if STRATEGY is set to 4 and TACTIC is set to 6 then the program will explore all the game tree to a depth of 4 half moves and then search for tactical moves to 6 half moves more. In this case, the search depth reaches 10 half moves.


According to the amount of memory you have I recommend you to edit the file board.txt and to change the number indicating how much memory the program uses to store transposition tables. Don't forget to let a few Mb for windows.

Total memory Memory to reserve
4 Mb 0
8 Mb 2 or 5 Mb
16 Mb 5 or 10 Mb
32 Mb 20 Mb
64 Mb 40 Mb
128 Mb 80 Mb
256 Mb 160 Mb


Unlike many others chess programs, E.T.Chess doesn't consider time.
Indeed the couple (STRATEGY,TACTIC) determines a precise level, whatever the computer running E.T.Chess is, it will play its move only when it has calculated all the moves required by the setting (S,T) and not before.
Thus E.T.Chess doesn't play according to a thinking time but according to a searching depth.

Current level of this program :

estimation based on :
Level estimation ( Athlon 550 Mhz )
1,[0;7] Instantaneous 0->1100 beginner
2,[2;7] Instantaneous 1100->1300 beginner
3,[2;7] Instantaneous 1300->1600 chess club player
4,[2;7] Instantaneous 1600->1900 good chess club player
5,[2;7] Blitz 1900->2100 strong player
6,[2;7] quick game 2100->2200 very strong player
7,[2;7] slow game 2200->2250 very strong player
8,[2;7] 2 hours / 40 moves 2250->... very strong player

NB : These estimations are made supposing that the opponent has no time limit when he plays.
If the opponent plays at the same speed than E.T.Chess then on a Pentium 90 the program reaches 2000 Elo at the level (3,2).

Technical information:

* Don't set the TACTIC level under 2 if you don't want to penalize the program.

* Increasing the TACTIC level over 6 will rarely improve the playing level but it will slow down the program.

Automatic Deepening

If you began the game with the program set to a level, then it will play all the game, including the endgame at this level. You'll notice that the program plays faster and faster when the pieces on the chess board are reduced. Moreover its strength will decrease in the endgame. To prevent such inconvenient E.T.Chess can increase its level automatically during the game if the AUTO DEEPENING option is turned on.


Do not increase the STRATEGY level arbitrarily:
Setting STRATEGY to a value:
* of 8 or more is only possible if there are few pieces on the board (endgame) or if you have a 10 GHZ Athlon ;-)
* >12 is only possible during an endgame : king + pawn Vs king + pawn

Interrupting E.T.Chess when it is thinking

Press Escape, a window appears enabling you either to force the move or to continue thinking.


I was unable to write a C program able to rival the world best chess programs written in assembly so I decided to build a program tactically quite weak (compared to FRITZ, not to a human being :) ) but using an evaluation function quite developed.
During its best days it can beat Chessmaster 6000 and GNU Chess thinking less time than them (But this is exceptional, I think it loses 75 % of its games ) .
However the evaluation function being frequently improved or damaged, I can't guarantee you precisely the current level of my program.



For any question, suggestion, criticism or encouragement, you can send me an email :

Enjoy yourself and copy this program as you want.
Thanks for having read this information page.