Chess Endgame Study

I came across this puzzle-like endgame study. Usually, opposite color bishops are draw-ish. Here's an absolutely extraordinary counter-example. Enjoy!

White to play and mate in 8.

Source: Winning Chess Endgames: Just the Facts!

1 Answer

This is beautiful.

I think we start with:

1. Bf2+ Kh5
2. g4+ Kh6
3. Kf6 Kh7(if 3... Bh7 then 4. Be3#)
4. g5 Kh8

At this point,

Black is in perpetual zugzwang. Black can only move its king around h7 and h8. So, our aim has to be to somehow get a check while covering the g7 square with our king. Currently, Black's f pawn covers the g6 square which renders our king pretty much stuck at f6. If we move the king away from f6, then black can run away with Kg7, Kf8, etc. Since White has a dark-squared bishop, they have to make sure they time the check such that the White king is on g6.

The next move:

5. Bd4 Kh7

Where do we stand?

White's bishop eyes the h8 square. Black has no other moves. It has to keep shuffling its king between h7 and h8. Currently, the Black king is on h7. The next move, it will be on h8. Thus, White can get its check when Black's king is on h8. Thus, White will have to lose a tempo.

Next move:

6. Be5(!) Kh8

Here,

White deliberately loses a tempo for Black's king to be in the perfect position for the mating net.

Now for the finishing touch:

7. g6 fxg6 (7... Bh7 8. Kxf7#)
8. Kxg6#

Final position:

• Great job. +1 for now and tick to follow shortly. It doesn't make much difference, but there's another option for black on move 7. Jan 28 at 23:24
• @DrXorile Right. Edited in that part.
– Sid
Jan 29 at 6:23
• Thanks. Beautifully answered. I really appreciate the breakdown of the logic rather than just a bunch of moves Feb 1 at 21:16