The Crazy Bishop

Introduction
Copyright notice and distribution policy
General concepts
Engine listeners and windows
How to use TCB with WinBoard
How to play games with TCB
How to set time controls
How to set hash table size
How to set the opening book
How to use endgame databases
How to manage game collections (EPD and PGN)
The "multiple" gear (n-best, ...)
Versions
The TCB mailing list

Introduction

The first public releases of TCB showed that a little documentation was required to help people using it. However, this documentation is far from being exhaustive. If it gives no good answer to your questions, you can ask the author directly by e-mail. He will add the answers to your questions to the next release of this doc.

Copyright notice and distribution policy

Copyright 1997-1999 by Remi Coulom. All Rights Reserved. Permission is granted to freely use and distribute this program, Provided that no charge is made for it and it is distributed unmodified. TCB comes with ABSOLUTELY NO WARRANTY.

I decided to distribute my chess program with the hope that people enjoy it in the same way I enjoyed using some other programs I downloaded from the internet. I also hope that distributing TCB will be an opportunity to get feedback from users, which may help to improve it. I would be particularly interested in having opinions about its weaknesses from chess players. Games are also welcome.

TCB is distributed with an interface that will allow users to connect it to internet chess servers. If you want to do it, please do not call it TCB nor TheCrazyBishop (I would like to reserve these names for my personal use), and indicate the URL of this page in its "finger" variables, as well as the hardware you are using.

I will not distribute the source code of TCB. I fear that distributing it can have unpleasant consequences, such as the risk of meeting a modified version in a tournament. I think that keeping the code secret is a good way to preserve the fun of competition, and the magic of computer chess.

General concepts

TCB has a powerful object-oriented user interface. The way it works is very close to graphic user interfaces like Windows : you can open sub-interfaces, switch from one to the other, etc. These interfaces share some basic commands, and are specialized with some specific commands (in the same way, graphic windows share some basic components such as a border, a title, a client area, and are specialized with specific components).

Basic commands

They are at the top of the list when you enter ? at the command prompt :

Syntax for command lines
~~~~~~~~~~~~~~~~~~~~~~~~
<command> <parameters> [< <input>] [>[>] <output>] [;<comment>]

Universal commands
~~~~~~~~~~~~~~~~~~
x .............. to close this console interface
p .............. to go to the parent interface
children ....... to list children interfaces
child <n> ...... to select a child interface

echo <params> .. to repeat <params> to the output stream
! [<command>] .. to make a system call
prompt [on|off] to show|hide the command prompt
myself ......... to call recursively this user interface

Moving from one interface to another

The four first commands are used to switch from one interface to the other. There are three kinds of interfaces. You can see the kind of user interface you are using thanks to the command prompt.

Modal interfaces : indicated by a "-" in the prompt. The only way to leave a modal interface is to close it.
Modeless interfaces : indicated by a "/" in the prompt. You can leave a modeless interface by closing it or by going to the parent interface
Permanent interfaces : indicated by a "|" in the prompt. The only way to leave a permanent interface is to go to the parent interface. You can not close a permanent interface manually. It is closed automatically when its parent is closed

Here is an example demonstrating these three kinds of user interfaces :

1. n(00:05:00,00)>chesslib
1. n(00:05:00,00)|ChessLib>pos
1. n(00:05:00,00)|ChessLib/Position>setfen k//K w - -
1. n(00:05:00,00)|ChessLib/Position>p
1. n(00:05:00,00)|ChessLib>pos
1. n(00:05:00,00)|ChessLib/Position>p
1. n(00:05:00,00)|ChessLib>children
1 : Position
2 : Position
1. n(00:05:00,00)|ChessLib>child 2
1. n(00:05:00,00)|ChessLib/Position>fen
k7/8/K7/8/8/8/8/8 w - - 0 1
1. n(00:05:00,00)|ChessLib/Position>p
1. n(00:05:00,00)|ChessLib>child 1
1. n(00:05:00,00)|ChessLib/Position>fen
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
1. n(00:05:00,00)|ChessLib/Position>x
1. n(00:05:00,00)|ChessLib>children
1 : Position
1. n(00:05:00,00)|ChessLib>p
1. n(00:05:00,00)>chesslib
1. n(00:05:00,00)|ChessLib>children
1 : Position
1. n(00:05:00,00)|ChessLib>child 1
1. n(00:05:00,00)|ChessLib/Position>fen
k7/8/K7/8/8/8/8/8 w - - 0 1
1. n(00:05:00,00)|ChessLib/Position>movegen
1. n(00:05:00,00)|ChessLib/Position-MoveGenerator>lml
Ka5 Kb5 Kb6
1. n(00:05:00,00)|ChessLib/Position-MoveGenerator>x
1. n(00:05:00,00)|ChessLib/Position>x
1. n(00:05:00,00)|ChessLib>children
1. n(00:05:00,00)|ChessLib>p
1. n(00:05:00,00)>x

Other basic commands

echo ouputs a copy of its parameters. For instance :

1. n(00:05:00,00)>echo Hello everybody !
Hello everybody !

! is used to make a system call. For instance :

1. n(00:05:00,00)>! dir *.htm

Le volume dans le lecteur E est COMPRESSÉ
Le numéro de série du volume est 1D01-253B
Répertoire de E:\REMI\tcb\WWW

REMI    HTM            353 31/01/97 21:48 remi.htm
COPYLIB HTM         26 206 27/01/97 18:08 copylib.htm
TCB     HTM          4 808 05/02/97 13:20 tcb.htm
TCBUSER HTM            237 08/02/97 18:16 tcbuser.htm
        4 fichier(s)              31 604 octets
        0 répertoire(s)       28 000 256 octets libres

prompt on shows the command prompt, prompt off hides it.

myself is a very powerful command that, combined with the < redirection operator, allows the use of command scripts. For instance, myself <blitz.cui will read the blitz.cui file and execute all its commands as if they were typed at the prompt.

Engine listeners and windows

Engine listeners are special objects that monitor the chess engine. Console interfaces for engine listeners have their prompt starting with special characters indicating the current gear of the engine :

(@n)EngineControl>

(@i) for infinite gear, (@a) for active gear, (@p) when pondering, ...

All engine listener console interfaces share the same command:

Engine Listener Commands
~~~~~~~~~~~~~~~~~~~~~~~~
wait [on|off] ... set wait mode

The wait mode indicates whether the prompt is printed right away after the completion of the previous command. If the wait mode is off, the engine loops until the user has pressed a key before printing the prompt. This behaviour is the only way to have the GUI work correctly. As soon as a prompt is printed and the program is waiting for user input on the console, all other windows of the program freeze. If you want to use windows and they are frozen, make sure you are in a listener interface (with a @ in the prompt) and that the wait mode is on. If it is the case then just enter an empty command in the console and the windows should behave normally.

How to use TCB with WinBoard

WinBoard is a graphical user interface that will let you play games with TCB, run matches against other chess engines or connect TCB to an internet chess server. More details about WinBoard can be found at Tim Mann's chess page.

The tcbxinit.cui file that is distributed with tcb gives an example of initialization file that can be used to set parameters for a game with WinBoard. Passing tcbxinit.cui to tcb on the command line (i.e. calling "tcb tcbxinit.cui") will set search parameters as specified in the file.

How to play games with TCB

The following sequence of commands will set TCB to play a game against the user, via the graphical board. Of course, you will have to use other commands in order to set opening book, time control, hash tables or endgame tablebases, as explained in other sections of this document.

(@n)EngineControl>board
EngineControl-Window>win on
on
EngineControl-Window>x
(@n)EngineControl>tournament
(@n)EngineControl|Tournament>gaum a
Active
(@n)EngineControl|Tournament>gacm p
Ponder

To start the game as White, simply enter moves on the board by dragging a piece with the mouse or enter a move at the command prompt. To let the computer play the first move, you can use the setgear a command. The ? command will give you a list of useful commands that can be used to set other parameters. Board parameters can be set by right-clicking on the board window to open a pull-down menu.

How to set time controls

Here is a commented command sequence to set a complex time control :

(@n)EngineControl>engine
EngineControl-Engine>wtc

Time controls can be set independently for White and Black. This example will set the time control for White only.

EngineControl-Engine-TimeControl>disp

Moves ............: 0
fResetClock ......: 0
Total time .......: 00:05:00,00
Time per move ....: 00:00:07,00
Next time control : no

This is the default time control : all moves in 5 minutes with 7 seconds per move

EngineControl-Engine-TimeControl>setmoves 40
EngineControl-Engine-TimeControl>settotal 01:00:00
EngineControl-Engine-TimeControl>setpermove 00:00:00
EngineControl-Engine-TimeControl>disp

Moves ............: 40
fResetClock ......: 0
Total time .......: 01:00:00,00
Time per move ....: 00:00:00,00
Next time control : no

The time control is now 40 moves in 1 hour, with one more hour of time to play added every 40 moves.

EngineControl-Engine-TimeControl>setreset
EngineControl-Engine-TimeControl>createnext
EngineControl-Engine-TimeControl>next
EngineControl-Engine-TimeControl-TimeControl>setmoves 0
EngineControl-Engine-TimeControl-TimeControl>settotal 00:05:00
EngineControl-Engine-TimeControl-TimeControl>setpermove 0
EngineControl-Engine-TimeControl-TimeControl>disp

Moves ............: 0
fResetClock ......: 0
Total time .......: 00:05:00,00
Time per move ....: 00:00:00,00
Next time control : no

EngineControl-Engine-TimeControl-TimeControl>x
EngineControl-Engine-TimeControl>disp

Moves ............: 40
fResetClock ......: 1
Total time .......: 01:00:00,00
Time per move ....: 00:00:00,00
Next time control : yes

Now, the time control is 40 moves in 1 hour. After 40 moves, the clock is reset and the rest of the game must be played in 5 minutes.

How to set hash table size

Hash tables are used to store analyzed positions, so that they need not being analyzed again. Hash tables save a lot of time in the search, especially in endings. The bigger they are, the better TCB plays. To set this size you can use the following commands :

special
size 10000000
x

This will use approximately 10 megabytes of memory for hash tables. It is very important to make sure that you have enough memory available to store the entire hash table. If the hash table is too big then memory will be swapped to the disk, slowing down the program considerably.

How to set the opening book

TCB can read book in PGN format like this :

(@n)EngineControl>special
EngineControl-TCB>pgnbook <book.pgn
.....
9512 bytes
EngineControl-TCB>x
(@n)EngineControl>

Loading the book with the pgnbook command may take some time if the file is big. Dots indicate the progress of this operation. When it is over, the number of bytes used by the book in memory is indicated. Note that you should load the opening book before setting hash table sizes, because the operation of loading the book can temporarily use a lot of memory.

Only the first game of the PGN file is read. This game should contain variations and NAGs (Numeric Annotation Glyphs, like ?, ??, ?!, ...) indicating bad moves. Moves without a NAG are considered as good. Moves with a NAG are considered as bad (even if the NAG is !). TCB chooses at random between all good moves in a position, with an equal probability for every move.

TCB provides a lot of functions that can help in building or editing books. Below are some examples of what can be done.

Converting a .fbk (Fritz book) file to a .pgn file that TCB can read :

Building your own opening book :

(@n)EngineControl>chesslib
EngineControl|ChessLib>cbgame
EngineControl|ChessLib-Game>reset
EngineControl|ChessLib-Game>cursor
EngineControl|ChessLib-Game-GameCursor 1. >add e2e4
EngineControl|ChessLib-Game-GameCursor 1. e4>next
EngineControl|ChessLib-Game-GameCursor 1... >add e7e5
EngineControl|ChessLib-Game-GameCursor 1... e5>prev
EngineControl|ChessLib-Game-GameCursor 1. e4>add d2d4
EngineControl|ChessLib-Game-GameCursor 1. d4>next
EngineControl|ChessLib-Game-GameCursor 1... >add d7d5
EngineControl|ChessLib-Game-GameCursor 1... d5>add a7a5
EngineControl|ChessLib-Game-GameCursor 1... a5>nag 2
EngineControl|ChessLib-Game-GameCursor 1... a5?>next
EngineControl|ChessLib-Game-GameCursor 2. >add e2e4
EngineControl|ChessLib-Game-GameCursor 2. e4>prev
EngineControl|ChessLib-Game-GameCursor 1... a5?>prev
EngineControl|ChessLib-Game-GameCursor 1. d4>add a2a3
EngineControl|ChessLib-Game-GameCursor 1. a3>nag 2
EngineControl|ChessLib-Game-GameCursor 1. a3?>next
EngineControl|ChessLib-Game-GameCursor 1... >add e7e5
EngineControl|ChessLib-Game-GameCursor 1... e5>x
EngineControl|ChessLib-Game>treeview
______e4______e5
      d4______d5
       |     a5?______e4
     a3?______e5
EngineControl|ChessLib-Game>pgn 3
[Event ""]
[Site ""]
[Date "1998.11.07"]
[Round ""]
[White ""]
[Black ""]
[Result "*"]

e4 (d4 (a3? e5) d5 (a5? e4)) e5 *

EngineControl|ChessLib-Game>pgn 3 >mybook.pgn
EngineControl|ChessLib-Game>x
EngineControl|ChessLib>p
(@n)EngineControl>

Of course, these commands can be used to edit an existing opening book. For instance, to remove the French defense from book.pgn and write the result in newbook.pgn :

EngineControl|ChessLib-Game>readpgn <book.pgn
EngineControl|ChessLib-Game>cursor
EngineControl|ChessLib-Game-GameCursor 1. d4>nextvar
EngineControl|ChessLib-Game-GameCursor 1. e4>next
EngineControl|ChessLib-Game-GameCursor 1... e5>nextvar
EngineControl|ChessLib-Game-GameCursor 1... c5>nextvar
EngineControl|ChessLib-Game-GameCursor 1... e6>nag 2
EngineControl|ChessLib-Game-GameCursor 1... e6?>x
EngineControl|ChessLib-Game>pgn 3 >newbook.pgn

Merging a collection of PGN games into a single tree

EngineControl|ChessLib>pgnfile file.pgn
EngineControl|ChessLib-GameFile>merge
EngineControl|ChessLib-GameFile>x
EngineControl|ChessLib>cbbook
EngineControl|ChessLib-Book>reset
EngineControl|ChessLib-Book>add
EngineControl|ChessLib-Book>reducedtree
EngineControl|ChessLib-Book>x
EngineControl|ChessLib>cbgame
EngineControl|ChessLib-Game>pgn 3 >merged.pgn
EngineControl|ChessLib-Game>treeview 9
______d4______d5______c4______e6_____Nf3_____Nf6_____Nc3_____Ne4_____Qb3
       |                      c6_____Nf3_____Nf6_____Nc3______e6______e3
       |                    dxc4_____Nf3_____Nf6______e3______e6____Bxc4
       |                                       |             Bg4____Bxc4
       |                                      a6______e3______e6____Bxc4
       e4______c5_____Nf3_____Nc6______d4____cxd4____Nxd4_____Nf6_____Nc3

How to use endgame databases

TCB supports two file formats for endgame databases : the old format by Steven J. Edwards and the new improved format by Eugene Nalimov. You can use both at the same time. TCB will first try to find the file in the new format. If it is not available, it will try to use the old format instead. Note that you should not use files in the old format that have pawns on both sides. They have errors because en passant captures were not handled correctly. The new format is also significantly more compact.

Besides the instructions below, another parameter you can tune (it is the same for both formats) is the search depth in hundredth of a ply at which endgame databases are not used any more. The default should be 400. You should increment this value to 500 or 600 if you read the files from a slow drive or through a network, for instance.

Obsolete format (Steven J. Edwards)

You can tell TCB to use SJE files with the tblist command in the engine-specific interface. For instance, assuming that you have tablebases in the c:\tb directory, you can use the following script to make TCB use them:

special
tblist
add c:\tb\kqk.tbw
add c:\tb\kqk.tbb
add c:\tb\krk.tbw
add c:\tb\krk.tbb
;(...)
x
x

New format (Eugene Nalimov)

Parameters can be set in the chesslib interface as shown below :

If the cache size is not large enough, tablebases will not be used. 1000000 should be a good default. You might like to use a different value depending on your hardware and the set of tables you have. You can see a commented initialization script in the file tcbxinit.cui which is included in the distribution.

EGTB files can be downloaded from Robert Hyatt's ftp site.

How to manage game collections (EPD and PGN)

The following is an example of commands entered to load a position in for analysis by the chess engine from a PGN or EPD file.

(@n)EngineControl>chesslib
EngineControl|ChessLib>! dir wm*.pgn

Le volume dans le lecteur C est MS-DOS_62
Le numéro de série du volume est 104C-13E8
Répertoire de C:\WINDOWS\Bureau\WMCC

WMCC15   PGN       163 367 02/11/97 15:19 WMCC15.PGN
         1 fichier(s)         163 367 octets
         0 répertoire(s)   59 047 936 octets libres
EngineControl|ChessLib>pgnfile wmcc15.pgn
EngineControl|ChessLib-GameFile>games
187
EngineControl|ChessLib-GameFile>list
[...]
182 1997.11.02 IsiChess / K6-200 AnMon / K6-200    15th WMCC
183 1997.11.02 MChess 7.0 / K6-2 Shredder 2.0 / Al 15th WMCC
184 1997.11.02 SOS / K6-200      Gandalf / K6-200 15th WMCC
185 1997.11.02 Toledo 2000 / P2- Crafty / Alpha 50 15th WMCC
186 1997.11.02 Woodpusher / K6-2 Diep / P2-300     15th WMCC
EngineControl|ChessLib-GameFile>load 183
EngineControl|ChessLib-GameFile-Game>pgn
[Event "15th WMCC"]
[Site "Paris"]
[Date "1997.11.02"]
[Round "11"]
[White "MChess 7.0 / K6-233"]
[Black "Shredder 2.0 / Alpha 533"]
[Result "0-1"]

1. e4 c5 2. Nf3 d6 3. Bc4 Nf6 4. e5 dxe5 5. Nxe5 e6 6. d3 Bd6 7. Ng4 Nbd7 8.
Bg5 Qb6 9. Nxf6+ gxf6 10. Bc1 Qc6 11. f3 b5 12. Bb3 Qc7 13. Nc3 Ba6 14. g3 c4
15. dxc4 bxc4 16. Ba4 O-O-O 17. Bb5 Bxb5 18. Nxb5 Bb4+ 19. c3 Qe5+ 20. Qe2 Qxb5
21. cxb4 Qxb4+ 22. Kf1 Ne5 23. Be3 h5 24. Rc1 Nd3 25. Rc2 Kb8 26. Rg1 Rhg8 27.
b3 c3 28. Kg2 Rd5 29. Rd1 Rgd8 30. Rb1 Ka8 31. a3 Qb5 32. Kh1 Qc6 33. b4 Rf5
34. Rf1 Qc4 35. Rfc1 Qb3 36. Rxc3 Nxc1 37. Rxc1 Qd3 38. Qf2 Re5 39. Re1 Qxa3
40. f4 Red5 41. b5 Qa5 42. Kg2 Qxb5 43. Ra1 a6 44. Kh3 Rd3 45. Kh4 a5 46. Qe2
Rb3 47. Qe1 a4 48. Bg1 Kb8 49. Qf2 Qd7 50. Qc2 e5 51. f5 Rb4+ 52. Kh3 h4 53.
Bc5 Rb3 54. Qe4 hxg3 55. hxg3 Rb2 56. Ba3 Rh8+ 57. Kg4 0-1

a b c d e f g h

8 r n b q k b n r 8
7 = = = = = = = = 7
6 .   .   .   .    6
5    .   .   .   . 5
4 .   .   .   .    4
3    .   .   .   . 3
2 # # # # # # # # 2
1 R N B Q K B N R 1

a b c d e f g h

EngineControl|Tournament-EngineCursor>cursor
EngineControl|Tournament-EngineCursor-GameCursor 1. e4>next 1000
EngineControl|Tournament-EngineCursor-GameCursor 57... >x

a b c d e f g h

8 . k .   .   . r 8
7    .   q   =   . 7
6 .   .   . = .    6
5    .   . = #   . 5
4 =   .   Q   K    4
3 B .   .   . # . 3
2 . r .   .   .    2
1 R .   .   .   . 1

a b c d e f g h

EngineControl|Tournament-EngineCursor>x
(@n)EngineControl|Tournament>
(@n)EngineControl|Tournament>setgear i
00:00:00,00         1 ------ Depth = 1
00:00:00,00         1   -377 57... Qxf5+
00:00:00,00         1   +231 57... Ka7
00:00:00,00         1   +231 57... Ka7
00:00:00,00         1   +236 57... Rg8+
00:00:00,05         1   +419 57... Rg8+
00:00:00,05         2 ------ Depth = 2
00:00:00,05         2   +419 57... Rg8+ 58. Kh3 Rh8+
00:00:00,05         3 ------ Depth = 3
00:00:00,22         3   +493 57... Rg8+ 58. Kh3 Rb3 59. Kh2
00:00:00,27         4 ------ Depth = 4
00:00:00,33         4   +499 57... Rg8+ 58. Kh3 Rb3 59. Bc5 Rgxg3+
00:00:00,55         5 ------ Depth = 5
00:00:01,21         5   +503 57... Rg8+ 58. Kh3 Rb3 59. Bb4 Rgxg3+ 60. Kh2 Rh3+
00:00:01,76         6 ------ Depth = 6
(@i)EngineControl|Tournament>p
(@i)EngineControl>chesslib
EngineControl|ChessLib>epdfile e:\echecs\tests\wac.epd
EngineControl|ChessLib-GameFile>load 1
EngineControl|ChessLib-GameFile-Game>copy
EngineControl|ChessLib-GameFile-Game>x
EngineControl|ChessLib-GameFile>x
EngineControl|ChessLib>p
(@i)EngineControl>tournament
(@i)EngineControl|Tournament>engcurs
EngineControl|Tournament-EngineCursor>setgame
EngineControl|Tournament-EngineCursor-Game>paste
EngineControl|Tournament-EngineCursor-Game>x

a b c d e f g h

8 .   .   .   .    8
7    .   .   .   = 7
6 .   .   . k .    6
5    .   .   =   . 5
4 =   =   . # .    4
3 # r   = # K   . 3
2 . # . R .   . # 2
1    .   .   .   . 1

a b c d e f g h

EngineControl|Tournament-EngineCursor>

Note also that if you want to browse a list of games from a big pgn file, you can redirect the output of the list command to a file and browse it with any text viewer. For instance, to view the list of games of the wmcc15.pgn file under Windows95, you can enter the commands below :

EngineControl|ChessLib>pgnfile wmcc15.pgn
EngineControl|ChessLib-GameFile>list >list.txt
EngineControl|ChessLib-GameFile>! start list.txt

The "multiple" gear

This is a special gear of the engine that can be used to analyze many moves at the same time from the same position. Parameters can be set in the engine console user interface using the commands below :

Multiple mode commands
~~~~~~~~~~~~~~~~~~~~~~
movelist ........ get the move list
resetlist ....... remove all moves from the move list
addlist <move> .. add <move> to the move list
nbest [n] ....... get [set] number of moves of n-best mode
threshold [eval] get [set] evaluation threshold in centipawns
mflags [flags] .. get [set] multiple mode flags :
                   1 : n best moves
                   2 : all moves
                   4 : moves from the move list
                   8 : moves > best - threshold

The mflags option can be a combination of these values. It can be interesting in a positionnal test to analyze 1 best move + the key move. For instance, you can analyze the best move of the starting position and 1. f4 like this :

(@n)EngineControl>tournament
(@n)EngineControl|Tournament>engine
EngineControl|Tournament-Engine>addlist f4
EngineControl|Tournament-Engine>nbest 1
1
EngineControl|Tournament-Engine>mflags 5
5
EngineControl|Tournament-Engine>setgear m
EngineControl|Tournament-Engine>x
[...]
00:00:02,64        60 ------ Depth = 4
00:00:02,64        61     +7 1. e4 Nf6 2. Nc3 e5
00:00:02,69        62     +7 1. d4 Nf6 2. Nf3 d5
00:00:02,69        63     +7 1. Nf3 Nf6 2. d4 d5
00:00:02,75        67     -9 1. f4 d5 2. Nf3 Nf6
[...]

You can notice in this example that in case of "1 best" mode, TCB will analyze more than one best moves if they have the same evaluation.

Versions

01/28/1997

First public release

02/08/1997

Added CWSDPMI and a version of tcbx that will run with Windows NT.
Added "bob" style for board display.
Some improvements in algorithms and opening book.
More user documentation.
Woody WoodPusher evaluation mode.

02/12/1997

fixed problems that could cause TCB to crash when pondering. This change affects djtcb.zip only

02/13/1997

typing the move command is not necessary any more.
bob board style fixed.
Added graphbd.zip, which gives a graphic representation of the board with styles 3 and 4.

02/20/1997

Big bug in pondering fixed.

0025 (03/23/1997)

From now on, versions will be given a number.
Distribution of the source code of chesslib.
Bigger opening book.
Some minor changes in the search algorithm and evaluation function.
tcbx proposes draw automatically after threefold repetitions and 50 moves rules (not doing so caused problems when used with Zippy).

0026 (03/31/1997)

Improvements in the engine, making tcb about 10% faster.
Evaluation improved to be more stable.
Minor changes and additions to the opening book.
simplex had problems with pondering on unix machines in the 0025 version. This is fixed now.

0027 (04/14/1997)

Aspiration added to PVS + many other speed improvements, making TCB about 20% faster on average.
Bigger opening book.
djtcbx is not distributed any more since now mstcbx is faster.
Some prolems in pondering (again !) fixed.
Graphbd is not distributed any more.
Auto232 interface added in chesslib.

0028 (05/03/1997)

No changes in the search algorithms.
The opening book is twice bigger.
Documentation for ChessLib and TCB's algorithms added.

0030 (06/23/1997)

Slightly augmented opening book (1066 nodes)
Transpositions in the opening book
Documentation on how to edit the opening book
Changes in the search algorithm, making TCB 20% faster on most positions at the price of being much slower on some sharp tactical combinations.
Time allocation problem fixed. This problem caused TCB to shorten its thinking time when searching a test suite with the epdtest command.

0031 (07/11/1997)

Bigger opening book (1255 nodes)
Slight improvements in move ordering
Fail-high/Fail-low moves are now rejected, only when eval == evalLow + 1

0032 (07/27/1997)

Slightly bigger opening book
Double hash table with smaller hash entries
Bug in the evaluation of futile moves corrected, resulting in a slower but more reliable search
Changes in move ordering

0033 (08/12/1997)

Very slight improvement in the quiescence search
A few more moves in the opening book (1292 nodes)

0034 (08/31/1997)

Small bug that could cause the display of weird evaluation values corrected

0035 (10/14/1997)

Bug in the detection of threefold repetition corrected. This bug caused TCB to think the position was not a draw when it had pondered a non-reversible move before and the opponent played a reversible move instead. This bug affected the 50 move rule as well.
Slight change in the opening book to avoid what happened against Dragon in the French CCC

0036 (07/13/1998)

Larger opening book (1594 nodes)

0037 (07/29/1998)

Small speed improvement

0038 (08/15/1998)

Small speed improvement

0039 (10/02/1998)

Tablebases
Small changes in evaluation
Evaluation modes are temporarily unavailable. They will be back in the future.

0040 (11/09/1998)

Larger opening book (1914 nodes)
Some parts of the doc rewritten
Multiple gear implemented

0043 (02/28/1999)

Linux binary released. Note however that it is about 30% slower than the Windows version on my P90.
Bug corrected : TCB now searches promotions in the quiescence search.
Deep changes in the architecture of the evaluation function. Woody Woodpusher, material only and mate only evaluation modes are back. The normal evaluation style is very close to the previous version, but programmed more efficiently and much easier to improve. Improvement of the evaluation function will be a priority for next versions. See woody.cui for an example of how to set the evaluation mode.
New command nodelimit in the xboard interface to limit the number of nodes searched in a move. This can make TCB play more weakly and make a funny opponent for a weak human player, especially if combined with the Woody Woodpusher evaluation style. Do not forget to disable pondering when using this command so that TCB does not take a lot of time to think when it predicts your move correctly.
Hash table algorithm changed. There is now only one table, the size of which is given in bytes. Do not forget to update your initialization files : size 20 will give a hash table with a single entry, not 1 million as before.
xboard new command does not clear the hash table any more. This should improve the playing strength when TCB is used in the Fritz interface. A new command, clearmem has been added in the engine interface so that it can be cleared manually.
A few moves added to the opening book
Node count is now displayed

0044 (10/11/1999)

Improved endgame selectivity
Evaluation of pawn races
Very minor changes to evaluation and time management heuristics
Overall improvement in playing strength should be close to zero

0045 (11/01/1999)

Support for Eugene Nalimov's EGTBs
3% speed improvement on my machine thanks to better compilation options
minor change to the way mate evaluations are managed in the search

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This is a mailing list dedicated to TCB, managed by John Perry (I thank him very much for this). You can subscribe by sending an empty e-mail to tcb-subscribe@jpunix.com. The goal of this list is mainly to inform users about new releases, give tips to use TCB, warn about bugs as they are discovered, etc.