The Anatomy Of An Endgame

P. Silva - T. Lassila
White to move

Here is a position from one of my recent games. As you can see, White is up a pawn and has a passed pawn. Black has majority on the kingside but his king is stuck in the square of the a-pawn. During the game I of course knew this position was a win for White, but it turns out that White must play carefully.

If 1. Kxb4? then 1... f5! 2. Kc5 (the white king can't block the black king from entering the square b7) g4 3. Kc4 g4 and Black queens at least one of the pawns.

If 1. Kb6? then 1...Kc8 2. a6 Kb8 (now the passed pawn can't queen) 3. Kc5 f5! and the situation is the same as before.

The key for White is to lose no time in stopping Black's push. 1. Kd4! f5 2. Ke3 Now the push fails: 2...g4 3. fxg4 fxg4 4. hxg4 h3 5. Kf3 and the king is in the square. Now Black has to stop two passed pawns with one king and thus loses. Trying to block the White king gives nothing for Black: 2...Kd6 3. f4! g4 4. hxg4 h3 5. Kf3 and again White wins.

What happened in the game then? White played: 1. Kb6? Kc8 2. Ka7 Kc7 and Black won easily.