thomastonk: I have tried to understand the endgame after 57.g5+ in depth, in particular the move 57.. Ke6!, which I called counter-intuitive yesterday. Well, roughly speaking, this move delays the decision, how to defend against White's pawns! With a king on e6, Black can (depending on White's next move) control g8 with the king or attack the pawns via f5. Now the details. The difference between 57.. Ke6! and 57.. Kf5? (or 57.. Ke5?) is the control of g8, see 58.g6 Bf8 59.Kxc2 a2 60.Kb2 Ba3+ 61.Kxa2 Bxc1:  click for larger view
The difference between 57.. Ke6! and 57.. Kg7? (or 57.. Ke7? or 57.. Kf7) is the distance to f5 after 58.Kxc2 a2 59.Bb2(+). If Black has played 57.. Ke6!, then 59.. Kf5 and 59.. Bf8 lead both to a drawn position, because Black can eliminate White's pawns.
Here is the drawn position after 59.. Kf5:  click for larger view
Finally, if Black played the king to the seventh rank, then White's win is not straightforward. After 57.. Kg7? 58.Kxc2 a2 59.Bb2+ Kh7, White's only winning move is 60.Bf6!, and now the final try 60.. Be7 61.Kb2 Bxf6+ 62.gxf6 yields a lost pawn ending:  click for larger view
Note that Black has unique defences after 60.Kb3? Be7! and 60.g6+? Kh6!. On the other hand, after 59.. Kf7 60.Bf6? Be7! works for Black. However, here 60.Kb3, 60.g6+ and others win. Chess is wonderfull. |