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Puzzle: Black to move and get an advantage
(sopuli.xyz)
Position from the game Zhongyi Tan vs Aleksandra Goryachkina, Semifinals of the World Cup 2023 Women's Section
This is too slow. After 1... Bxf4 2. Ng2/Kh1/Kg1 Ra1, white can simply take the pawn for free with 3. Rxb2, and black loses all the advantage.
Trading a bishop for a pawn (one pawn that wasn't passed and only in the third rank) is not a very good deal, and black makes no progress towards promoting. Also, in endgames, king activity tends to be more important that king safety.
The bishop is in danger and unsupported no matter where you move it.
What I meant with giving check with the rook was:
1โฆ Bxf4 2. Kh1/Kg1 Ra1+
That puts white in check with the rook, forcing the king to move, followed by b1Q. If then white takes the new queen at b1, she is protected by the rook at a1. Again, not the most elegant solution but at least black is not giving his promoted pawn away for nothing