Position is Everything
In pure opposite-colored bishop endgames the defender usually wants to construct a fortress on the squares that his bishop controls (see Endgame Corner 2). So material is often less important than positional factors. The following endgame, from Lars Bo Hansen’s excellent book How Chess Games are Won and Lost (GAMBIT 2008), caught my attention.
My feeling was that White is better, but somehow it should still be drawn with best defense, as the drawish margin is quite large in opposite-colored bishop endings. Yet Hansen managed to win, so I had to search for improvements.
A surprising decision, as usually the attacker wants to keep the rooks on the board. So 47.Bd4+ was necessary; e.g., 47…Kf7 (47…Ke7 48.Be5 Rb7 49.f4 Kf7 50.fxg5 hxg5 51.Rd8) 48.Be5 now Rxe6 is threatened 48…Ra8 (48…Rb7 49.Rd8 Ra7 (49…Be8 50.Rc8 with the threat Rc7+ as now the pure opposite-colored bishop endgame is won.) 50.Rh8 Ra2+ 51.Kg3 Re2 52.Bd6 Rd2 53.Bb8 Bf1 54.f4) 49.Rb6 Ra2+ 50.Kg3 and White has a strong initiative in all cases.
Black must act energetically to stop White’s plan. White wants to play f3-f4 and after gxf4 Bxf4 put his king on h4 and play g4-g5 hxg5 Kxg5 followed by h5-h6. Then put his bishop to e3, where it protects h6 and stops Black’s e-pawn (the important principle of one diagonal at work), so that White’s king can march to the queenside to win Black’s bishop. 48…e5! 49.Bc5 (49.Ke3 Bc6 50.Bc5 Kf7 51.Bd6 e4 52.f4
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