With the help of a tactical blow, White ensures himself a pair of connected passed pawns on the queenside. However, even one passed pawn, supported by the bishop, should be enough to win.

Black resigned, since after 36...fxe6 37.Rxb5 Rxa3 38.Rh5+, he will lose a bishop.

Black thought his knight on h5, which is heading for f4, was safe. If White plays...

then

and after taking the knight on h5, the white pawn on d4 hangs. However, White has the zwischenzug.

The Nh5 still hangs, whilst there is now a threat of 21.d6. White has a healthy extra pawn, and went on to win.

Losing the Bd8, which is X-rayed down the d-file by the white rook, would obviously be catastrophic for Black, because he would be unable to get out his queenside pieces. The only question is where the white knight should go, and the answer is easy to find:

On 25.b4, there would follow 25...b6, and there is nothing decisive.
Also not very effective is 25.Kf4 Re8 26.Nxe4 b6 – the black bishop comes out to d7, and Black can defend.

White is trying to weaken the dark squares in the opponent’s camp, so as to organise an attack on the king. But, the weakening of his own construction is something he has not noticed, and Black begins to land counterblows on the light squares:

After 18.Nc3, White has to lose precious time to regain the central pawn: 18...fxe5! 19.Rd1 Be8! (the right square to keep the d5-pawn under attack) 20.Ne4 Rc8 21.Qxe5 Rf5!, and ...Rf5xd5.