BRITISH CHESS PROBLEM SOCIETY

In this serieshelpmate Black plays a series of three moves to reach a position where White can mate in one. Each position in the black sequence must be legal, so the white king can only be checked on the final move. Part a) uses the normal board. The vertical cylinder in b) has the a and h files joined. The horizontal cylinder in c) has the first and eighth ranks joined, and finally the anchor ring in d) combines the vertical and horizontal cylinder boards.

In each part Black blocks b5 to allow b3 mate. a) solves by 1.h1Q 2.Qxd5 3.Qb5. On a vertical cylinder promotion to queen would give check, hence the solution is 1.h1R 2.Rh5 3.Rb5 (via a5). On a horizontal cylinder a queen blocking b5 would guard the b2 pawn from the rear, so the solution is 1.h1B 2.Bg2 3.Bb5 (via f1 and e8). Finally on the anchor ring White promotes to a knight then moves through h8 and h7 to a7. 1.h1S 2.Sa7 3.Sb5. Combining the four types of board with the four different promotions in such a light position is a remarkable achievement.

Jacob Hoover: Since all four possible pawn promotions are seen here, this is a bona fide AUW. (I guessed that it was an AUW after solving parts (a) and (b).)

Richard Stein: A guide to fairy chess indeed. With the files continuous, a queen or bishop checks the white king. The cleverest part about this problem is that with the bottom and top joined, a rook on b5 can spin around and capture a pawn on b3.

8th November 2021

Selected by Michael McDowell