Time to get moving!

Passive defence is prospectless, and the knight has no future on b1. It was essential to take urgent measures to activate his position, by giving back another pawn: 22.e5!. Admittedly, after the strengthening move 22...Qb6 (it is less accurate to start with 22...c4, since the other knight becomes active with 23.Nd4!; whilst after 22...Bxe5 23.f4, Black has to exchange the bishop that is the pride of his position, or lose one of his passed pawns on c6) 23.Ne4 c4+ 24.Kh1 Bxe5, Black nonetheless keeps some advantage.

Now it is all over – White has so placed his minor pieces that he has no possibility of organising counterplay.

The time-trouble phase is over and White resigned.

White wants to entrench his knight on d4, after which he can prepare an attack on the kingside with g3-g4 and f4-f5. The move ...h6-h5 will not bother him, because he can reply simply h2-h3. Of course, White’s plan is hard to implement, but it is potentially possible, and Black cannot afford to relax. Therefore, exploiting a fleeting chance, Black sharply changes the picture, forcing White onto the defensive:

A brilliant decision! Black solves all his problems, which consist of his inactive bishop, blocked by the enemy pawns, and his lack of space. The connected passed pawns created by the sacrifice are joined by the d5-pawn, and form a dangerous avalanche. The pawns have a long way to go to promote, and therefore Black had to realise that the position is fairly closed, and the white knight cannot organise counterplay on the kingside.

By playing 40...b4!?, it was possible to pose White greater problems.

Passive defence on the queenside does not lead to any happiness, and so White seizes the first chance for counterattack, which proves to be the saving resource.

This could also have been delayed until the next move, when the black rook stands on b5, but Black decided not to fight against the inevitable.