2024/07/18 DPA: "The Curious Case Of The Circuitous Queen"

Black to move.

Both Rook and Knight are pinned.

Material is even.

I see another triangulation, similar to Tuesday:  1. ... Qe1+  2. Kh2 Qh4+, forking the Rook.

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Note that even though the Knight attacks the Queen, the Knight is pinned so it cannot capture.

The key was seeing that the Rook was undefended and that a BQM [Backward Queen Move] was needed to fork the King and Rook.

Note that 1. ... Qe3+ works ONLY IF 2. Kh1 and Black can proceed as in the puzzle solution with 2. ... Qe1+.  But if White plays either 2. Kh2 or Kf1, Black loses the fork opportunity.