The whole of Black’s position hangs by the knight on e5, which defends the f7- and g6-squares. Therefore White played...

exploiting the fact that the hanging Bb5 still serves a purpose – it covers the c6- and d7-squares, not allowing the other black knight to replace its colleague on e5. By contrast, the pointless check 14.0-0+ Kg8 would create a threat of 15...hxg5, and White’s attack fizzles out.

He also loses after 14...Rh7 15.Bxe5 dxe5 16.Rd1 Nd7 17.Bc4!. It turns out that the apparently lost white bishop comes into the attack with decisive effect.

Black resigned.

The pawn pair b7-c6 prevents White from developing an attack on the enemy king, which is stranded in the centre. The correct decision is the crude but effective:

In the game, White offered the more valuable attacking knight for the pawn on c6 by playing 21.Nd5, but after 21...cxd5! 22.Nc7+ Kf7 23.Bxd5+ Ke7, there are no deadly bishop retreats, and continuing the variation with 24.Ra3 (24.Ne6 Qg4+ 25.Kf1 Be4 loses at once) 24...Ne5 25.Ne6 Qxc1+! 26.Qxc1 Rxd5 reveals that the advantage is now with Black.

The threat of a check on c7, plus the powerful major pieces, are deadly, e.g.:

Nothing comes from the check 22...Qg5+ 23.Kf1, and White repulses all threats.

Black is mated, without ever completing the development of his kingside.

The move ...g7-g5 has seriously weakened the long diagonal, which White exploits with the aid of a small tactical operation: