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
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 :
- Results solving chess problems
- Matches against others programs ( Chessmaster 6000, Chess Genius 5, GNU Chess )
- Matches against human players on the internet
- Games played at the St-Jacques' chess club in Clermont-Ferrand (France)
Level estimation ( Athlon 550 Mhz )
| STRATEGY,TACTIC || Thinking time || ELO || PLAYER TYPE |
| 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).
* 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.
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.
ADDITIONAL TECHNICAL INFORMATION : What is E.T.Chess made of
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.
- A lot of NegaMax and Alpha-Beta
- A quite advanced evaluation function
- Killer heuristic
- Null move heuristic
- Transposition tables
Very useful if E.T.Chess needs to calculate deeply :
calculating speed may be multiplied by 2 in the middle game
and by 10 in the endgame
- An opening book designed using the "Guide marabout des échecs"
- E.T.Chess comments your playing style in a quite irritating way
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.