Thursday, October 14, 2010

Chess endgame table base KRKB

The next on my list for endgame tables was the endgame of king and rook vs king and bishop. Theory says that games with rook vs bishop or knight are drawish as they contain mostly draws and a few easy to spot wins where the rook is able to capture the piece (e.g. by pinning it to the king).

The table proved the theory however there are a few positions where the side with the rook can force a win that is not that obvious. I find those positions and the paths to mate from them quite interesting. One example is the following board


From the first look this position seems to be a safe draw for black. White is not able to capture the bishop in the near future. But the final table shows that this position is a forced with for White in 29 moves. The only winning move is 1. Ke1. The bishop is captured in move 17. So it would require a rather deep calculation for an engine to see the win in that position.