2024/02/24 DPA: "Discovered X-Ray Attraction"

Black to move.

If 1. ... Bxc4  2. Qh6+ Kf6  3. Be7+ Rxe7  4. Qh8+ Kg5  5. f4#

Black strikes with 1. ... Rxf1+  2. Kxf1 Bxc4+  3. Kg1 Qe1+  4. Rxe1 Rxe1#

Because White threatens checkmate, any move that does not involved check, like 1. ... Bxc4, is too slow.

Today's explanation is rather brief because I do this real-time and this is what I saw.

The Rook sac attracted the King to f1 where the Bishop could check it while simultaneously opening up the Rook's control of the e file.  This then set up a double attack on e1 via the Queen and the X-Ray attack of the Rook [the Black Rook contests e1 through the White Rook].