The logic is not as simple as one would think (which makes the problem all the more interesting). The Breton adverse condition allows White to remove any black P when capturing Pe5. So White sets up a threat by removing a guarding bP … no, that is true only for the solution! Rf5-e5 actually sets up two threats (Sf5#, Rxe4#), and the bP removals on b7 and f7 serve as dual-avoidance effects (Sushkov-theme style). The removal of Pf3 in the solution rules out both threats by dual-avoidance effects, but lets in a new threat by removal of a guard (so this is a form a threat correction, too).
The appearance of all three thematic mates in every phase works quite seamlessly. I’m especially impressed with how Sf5# and Rxe4# are produced in the solution.
Hubert Gockel
October 24, 2019 00:16
I couldn’t have explained the contents better – so thank you very much, Kjell!
The logic is not as simple as one would think (which makes the problem all the more interesting). The Breton adverse condition allows White to remove any black P when capturing Pe5. So White sets up a threat by removing a guarding bP … no, that is true only for the solution! Rf5-e5 actually sets up two threats (Sf5#, Rxe4#), and the bP removals on b7 and f7 serve as dual-avoidance effects (Sushkov-theme style). The removal of Pf3 in the solution rules out both threats by dual-avoidance effects, but lets in a new threat by removal of a guard (so this is a form a threat correction, too).
The appearance of all three thematic mates in every phase works quite seamlessly. I’m especially impressed with how Sf5# and Rxe4# are produced in the solution.
I couldn’t have explained the contents better – so thank you very much, Kjell!