GnuChess5 strange bookmove

[Sune Larsson]

After 1.e4 Nf6 2.e5 GnuChess plays the blunder 2.-b6??
What's wrong ?
Sune

[Dann Corbit]

After 1.e4 Nf6 2.e5 GnuChess plays the blunder 2.-b6??
What's wrong ?

It is strange, because my copy does not do that. What opening book are you using?
E:\chess-5.00\src>gnuchess5
GNU 5.0 Chess (Corbit tweaked -- sorry)
Version 5.00 (September 1999)
Transposition table: Entries=1024K Size=32768K
Pawn hash table: Entries=256K Size=16384K
White (1) : go
Read opening book (book.dat)... Opening database: 59904 book positions.
In this position, 8 moves are book moves:
e4(57) d4(42) Nf3(30) Nf3(30) c4(2) g3(-19) g3(-19) b3(-19)
My move is : d4
Black (1) : Nf6
1. Nf6
white KQkq
r n b q k b . r
p p p p p p p p
. . . . . n . .
. . . . . . . .
. . . P . . . .
. . . . . . . .
P P P . P P P P
R N B Q K B N R
Read opening book (book.dat)... Opening database: 59904 book positions.
In this position, 5 moves are book moves:
Nf3(-78) Nf3(-79) Bg5(-100) c4(-107) Bg5(-145)

My move is : Bg5
Black (2) : e5
2. e5
white KQkq e6
r n b q k b . r
p p p p . p p p
. . . . . n . .
. . . . p . B .
. . . P . . . .
. . . . . . . .
P P P . P P P P
R N . Q K B N R
Read opening book (book.dat)... Opening database: 59904 book positions.
In this position, 0 moves are book moves.
Time = 5.0 Rate=70663 Nodes=[312336/42182/354518] GenCnt=543084
Eval=[35669/142559] RptCnt=4 NullCut=15487 FutlCut=86082
Ext: Chk=9170 Recap=1181 Pawn=3074 OneRep=490 Horz=168 Mate=0 KThrt=523
Material=[3650/3650 : 4450/4350] Lazy=[150/177] MaxPosnScore=[289/195]
Hash: Success=39% Collision=25% Pawn=82%
My move is : dxe5
Black (3) :


My ftp site

[Pete Galati]

After 1.e4 Nf6 2.e5 GnuChess plays the blunder 2.-b6??
What's wrong ?
Sune

Something's wrong with that, are you useing the book that Dann supplied with the program? There must be a mistake in that book. You could compile a new book by copying the book.pgn file into the same directory as the exe file, and then in the GNU program (not in Winboard), use the command "book compile". That will make a smaller opening book but it will be the one that was made for that program by Stuart Cracraft.
Pete

[Sune Larsson]

After 1.e4 Nf6 2.e5 GnuChess plays the blunder 2.-b6??
What's wrong ?

It is strange, because my copy does not do that. What opening book are you using?
E:\chess-5.00\src>gnuchess5
GNU 5.0 Chess (Corbit tweaked -- sorry)
Version 5.00 (September 1999)
Transposition table: Entries=1024K Size=32768K
Pawn hash table: Entries=256K Size=16384K
White (1) : go
Read opening book (book.dat)... Opening database: 59904 book positions.
In this position, 8 moves are book moves:
e4(57) d4(42) Nf3(30) Nf3(30) c4(2) g3(-19) g3(-19) b3(-19)
My move is : d4
Black (1) : Nf6
1. Nf6
white KQkq
r n b q k b . r
p p p p p p p p
. . . . . n . .
. . . . . . . .
. . . P . . . .
. . . . . . . .
P P P . P P P P
R N B Q K B N R
Read opening book (book.dat)... Opening database: 59904 book positions.
In this position, 5 moves are book moves:
Nf3(-78) Nf3(-79) Bg5(-100) c4(-107) Bg5(-145)

My move is : Bg5
Black (2) : e5
2. e5
white KQkq e6
r n b q k b . r
p p p p . p p p
. . . . . n . .
. . . . p . B .
. . . P . . . .
. . . . . . . .
P P P . P P P P
R N . Q K B N R
Read opening book (book.dat)... Opening database: 59904 book positions.
In this position, 0 moves are book moves.
Time = 5.0 Rate=70663 Nodes=[312336/42182/354518] GenCnt=543084
Eval=[35669/142559] RptCnt=4 NullCut=15487 FutlCut=86082
Ext: Chk=9170 Recap=1181 Pawn=3074 OneRep=490 Horz=168 Mate=0 KThrt=523
Material=[3650/3650 : 4450/4350] Lazy=[150/177] MaxPosnScore=[289/195]
Hash: Success=39% Collision=25% Pawn=82%
My move is : dxe5
Black (3) :

I use the book.dat /936kB/ that followed GnuChess5. This strange thing
happens when I play white vs GC. Normal Alekhines defence: 1.e4 Nf6 2.e5,
but then the weird 2.-b6?? which of course loses a piece after 3.exf6.

Sune