Corresponding Squares: Triangulation with an Advanced Passed Pawn
White to play and win, after Fahrni - Alapin
PlayThe kings are on the right squares, but it is your move. The rule: find the squares where his king must answer yours, then spend a spare move. Your two spare squares touch each other and his do not, so you can hand him the move.
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Corresponding Squares Behind the Passed Pawn
White to play and win · Win against perfect defense
Waking the engine…
The theory
Watch the method: press play to see the winning idea run, or step through it move by move.
d5 touches both c5 and d6, and c8 touches both c7 and d8, so d5 and c8 correspond too. That is where the kings stand, with you to move. Pushing gets you nothing: after c7 he simply takes with Kxc7.
This is Fahrni against Alapin, 1912, the standard exercise for building a corresponding-squares map from scratch.
Start with the obvious pairs. Kings on d6 and d8 is reciprocal zugzwang. So is c5 against c7. In both, whoever is to move has to give way.
Extend the map. d6 and c5 both touch d5; d8 and c7 both touch c8. So d5 corresponds to c8. That is the position in front of you, with you to move, which is the wrong way round.
Count the spare squares. Adjoining d5 and c5 you have two more: c4 and d4. Adjoining c7 and c8 Black has b8 and d8, but they are two king moves apart while your c4 and d4 are neighbours. That is the whole win: Kc4 Kd8, Kd4 Kc8, Kd5 and the map is back with Black on move.
In this drill the defender knows the map too. Kd6, Kc8, c7 and the pawn queens.
Keep going
The Stalemate That Saves
Black to play and draw
Corresponding Squares: Dedrle's Draw
Black to play and draw
The Wing Pawn Is Bait
White to play and win
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