Bregenz Lessons V: Revisiting Bishops v Structure

THREE days age I posted about the battle between a bishop-pair and a superior pawn-structure, namely in the case of Black using the king's bishop to capture the white queen's knight on c3.

I wrote that, whatever the objective merits of such an exchange, the important thing is probably knowing how to handle the resulting position, rather than which side the engines feel has a slight edge.

Such knowledge is a big help in knowing when to make such an exchange, and, from the other side, knowing when there is no need to prevent it.

The following position arose in my game from round five of the Bodensee Senioren.

White has just played 21.Bg4-f3 - should Black capture on c3?

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White has the better pawn-structure and the more-coordinated pieces, leading Stockfish16 and Komodo14.1 to award White the upper hand.

The game saw 21...Bxc3!?, which smashes White's queenside, but leaves Black weak on the dark squares.
The exchange probably favours White, not least because the white weaknesses are hard to get at, and Black is left with two awkwardly placed minor pieces.

Stockfish16 and Komodo14.1 reckon the exchange favours White by the equivalent of about a half-pawn, in a position that already favours White.

LESSON: bishop-pair v pawn-structure battles can be hard to evaluate, but a useful rule-of-thumb is that when you have a bad bishop (in this example the black queen's bishop) it is rarely a good idea to give up your good bishop.