Solution
12… ♝b5+ 13. ♚g1 O-O-O 14. c4 ♝xc4
The position
This advanced puzzle (rating 2088) asks Black to move to find the winning idea. It features these themes: Middlegame, Castling.
It is Black to move. Look for the tactic hiding in the position — Middlegame, Castling. Drag a piece on the board to play your move; the puzzle will tell you if you found the best continuation.
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