Monday, December 11, 2006

Mating With KBB vs. K

This one I never even tried until a couple of days ago, as I thought it would we quite trivial to line up the bishops and force the king out of space. But now that I've actually drilled it, I realize there was a good chance to stalemate in time trouble, and that the efficient mating sequence actually demands some technique.

The general idea is to drive the defending king into any corner, and mate him. It's easiest done setting the bishop pair side by side as close to the defender as possible, confining him into a triangular area against the edge. Then you just move your king up, take a couple of squares and squeeze a diagonal off every time the defender retreats, until it's against the edge. Then you pick a corner, and force the king towards it by blocking it from behind with the bishops.

In the corner, confine it against either edge, line up the bishops to take the final squares with check, lose a tempo if needed, then check and mate.


A blitzed example against Chessmaster 9000:

[White "wormwood"]
[Black "Chessmaster"]
[Result "1-0"]
[Setup "1"]
[FEN "7K/3B4/8/8/8/2B2k2/8/8 w - - 0 1"]
1.Be6 Ke4 2.Bf6 Kd3 3.Kg7 Ke4 4.Kg6 Ke3 5.Kg5 Kd2 6.Kf4 Kd3 7.Be5 Ke2 8.Bd5 Kd3 9.Kf3 Kd2 10.Be4 Kc1 11.Bd4 Kd2 12.Kf2 Kc1 13.Ke3 Kd1 14.Bb2 Ke1 15.Bc2 Kf1 16.Kf3 Kg1 17.Bc3 Kh2 18.Bf5 Kg1 19.Kg3 Kh1 20.Bd3 Kg1 21.Bd4+ Kh1 22.Be4# 1-0

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