Black gives up a pawn, instead of accepting utter passivity after 23…♖f8 24.♖hf1 ♗f6, when the difference in strength between the opposite-colored bishops is obvious. After 25.♕b5, White will follow up with ♖d1-d7, and have a big, big advantage.

White has to defend the c2-pawn, but the bishop was active again nine moves later, while Black had dropped the a4-pawn, too:

He has spotted the weak d6-square.

This octopus rules! Black’s rooks are at a loss.

20…b6? is refuted by 21.♕f3.

And White won material and later the game: …1-0 (50).

White increases his space advantage, which results from his central passed pawn, and intends to drive the black pieces further back.

15…♗c6 16.f3 a6 17.b4 cxb4 18.axb4 ♕d8

18…♕xb4 19.♖fb1 is a trivial queen catch.