One by Leonid Kubbel

In Tal's Winning Chess Combinations (1979) by Mikhail Tal and Victor Khenkin, each section concludes with several exercises. There are six at the end of chapter II, "The Bishop". Five gave me minimal difficulties. That is, I solved most quickly and all accurately. The sixth, however, vexed me. I looked at it several times over the course of two evenings. Finally, having given up, I entered it as a position in Stockfish on the iPad and played the side that was supposed to lose--Black. The game was drawn by repetition because I could not find a way to convert my material advantage.

The failure of Stockfish lessens my pain.* The exercise was composed by Leonid Kubbel (1891-1942).

White to move

The authors of Tal's Winning Chess Combinations offer, "it all happens in six moves" (53).


*Stockfish on my desktop computer solved the exercise in about five seconds.