Solution
40. ♜xb7+ ♚a5 41. b4+ ♚a6 42. ♜b6+ ♚a7 43. ♜a3#
The position
This advanced puzzle (rating 2069) asks White to move to find the winning idea. It features these themes: Mate in 4.
It is White to move. Look for the tactic hiding in the position — Mate in 4. 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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