Similar positions frequently arise in the Queen’s Indian Defence, and the device used now by White is a typical one:

In this case, the knight jump leads to a gain of material, but sometimes it is played just with the intention of transferring the knight to a5 or e3, or to attack an enemy queen on b6, exploiting tactical motifs as the knight cannot be captured, because the d5-pawn is pinned along both file and diagonal.

And White won.

Black has the advantage of the two bishops and his pieces are actively placed, excellently supporting his pawn duo. Now, there follows a break, which crowns Black’s build-up:

25.exd4 Bc6! 26.Qc4 Bxf3 27.gxf3 cxd4 28.Na4 Qb5 29.Qe2 Rc7! 30.b3 Qxb3 31.Qxa6 Qxf3 also offers no hope of survival.

The white pawn islands on dark squares are indefensible.

Black had many ways to win, but this prophylactic move, defending against a possible fork on f5, is the most technical.

Hanging pawns are good when they are supported by their own pieces, but in this position, the Ra1 is ‘sleeping’, and the Nd2 is under an X-ray attack along the d-file.

Hit by a sudden blow, White does not find the inner strength to put up serious resistance, and he loses easily. More tenacious was 24.d5, although here too, after 24...Rh6 25.Nf3 (on 25.e5, there follows the simple 25...Bf8, and the pawn on d5 is undefended) 25...Nd3 26.Re2 Nxb2 27.Rxb2 Bc5+ 28.Kh1 f5, Black breaks up the white centre and wins a pawn.