Piece handicap elo diff, an idea for Kai Laskos for testing

[lkaufman]

Thanks. Your last result does suggest (not too strongly) that the f1 bishop is worth slightly more, as Komodo already believes, as theory says, and as makes sense because only the f1 bishop can check the enemy king on its home square or either of its castled squares. But it's a very small difference, as your result shows. So I guess there's nothing for us to improve here. If you find anything else surprising by this sort of testing, please let us know.

After I played with Pgn-extract this morning, I tried to make use of one of its features, with an interesting, unrelated to topic result. It seems that Komodo and Stockfish have different castling patterns. While Komodo is more focused on kingside castling, Stockfish is a bit more varied, making more queenside castlings, more opposite side castlings and more no castlings at all. Be warned that these were depth=7 games.

Code: Select all

Komodo 10
8,000 games depth=7
Castling

Kingside : 5547
Queenside:  791
No castl : 1662 
Opposite :  228

Code: Select all

Stockfish dev
8,000 games depth=7
Castling

Kingside : 4718
Queenside: 1060
No castl : 2222 
Opposite :  278

Since Kingside castling is the norm, more queenside castling means more opposite side castling. As to why SF likes queenside more, I'm pretty sure this is due to eval differences, perhaps piece square tables in particular. I think that the ratio of kingside to queenside in grandmaster play is much closer to your Komodo result than your Stockfish result, but my memory could be wrong on this point.

[Laskos]

Thanks. Your last result does suggest (not too strongly) that the f1 bishop is worth slightly more, as Komodo already believes, as theory says, and as makes sense because only the f1 bishop can check the enemy king on its home square or either of its castled squares. But it's a very small difference, as your result shows. So I guess there's nothing for us to improve here. If you find anything else surprising by this sort of testing, please let us know.

After I played with Pgn-extract this morning, I tried to make use of one of its features, with an interesting, unrelated to topic result. It seems that Komodo and Stockfish have different castling patterns. While Komodo is more focused on kingside castling, Stockfish is a bit more varied, making more queenside castlings, more opposite side castlings and more no castlings at all. Be warned that these were depth=7 games.

Code: Select all

Komodo 10
8,000 games depth=7
Castling

Kingside : 5547
Queenside:  791
No castl : 1662 
Opposite :  228

Code: Select all

Stockfish dev
8,000 games depth=7
Castling

Kingside : 4718
Queenside: 1060
No castl : 2222 
Opposite :  278

Since Kingside castling is the norm, more queenside castling means more opposite side castling. As to why SF likes queenside more, I'm pretty sure this is due to eval differences, perhaps piece square tables in particular. I think that the ratio of kingside to queenside in grandmaster play is much closer to your Komodo result than your Stockfish result, but my memory could be wrong on this point.

Right, the ratio kingside/queenside in human GM games is about 10:1, for Komodo the ratio is 7 and for Stockfish 4.5.