Black resigned.

The black king is in danger. The f7-square looks inadequately defended, and the set-up Qh7-h8 and Bb1-h7 is crying out to be played. However, the Nf5 prevents this, and after the straightforward 27.Qh8, there follows the simple 27...g7-g6. A nice tactic comes to the rescue:

In the game, White did not find this move, and after 27.Rd1 Qc6 28.Qxg8+ Kxg8 29.Ne7+ Kf8 30.Nxc6 Rxc6 Black managed to save this difficult endgame.

In the event of 27...Qxe7 28.Rxe7, White has a decisive material advantage.

And Black is mated.

White has a good position in the centre, but his king is on an unpleasant diagonal, where it faces threats of checks. This is felt especially in conjunction with the position of the Bf4, which is currently cut off by the e3-pawn from the diagonal a5-e1. This circumstance could be exploited with the surprising...

The game went 15...Qb5+ 16.Kd2 Qa5 17.Ke2 Qa6+ 18.Kd2 Qa5 19.Ke2 Qa6+, with a draw by repetition.

With this move, Black lures one of the white pieces to c2.

On 17.a3, Black wins immediately with 17...Bb4+!.
If White defends the king with 17.Qd3, then after 17...Qa5+ 18.Ke2 Nxa1 19.Rxa1 Qa4, he not only loses the exchange, but also concedes the c-file, which gives Black a decisive advantage.

After 18.Qxc2 Bb4+ 19.Kd1 Qf1+, White is mated.