The BDS Website

Stephen Emmerson & BDS

Die Schwalbe, 1997

R#2
LEOs e1; b4
PAO b6, c4, h2
VAO h8; a7, c1, d8

1...VAb8 2.PAf6       VAdc7#
1...VAc7 2.PAf6       VAb8#
1...LEb5 2.almost any Bc5#

1.PAg4   ()

1...VAb8 2.Bd5+       LEd6#
1...VAc7 2.Be6+       LEd6#
1...LEb5 2.PAc4       Bc5#

In the set play there are VAO + VAO anti-battery mates both introduced by the same self-block on f6. Not very interesting, and even more boring are the multiple continuations after 1...LEb5.

After the key, the black VAOa7 is the only guard on d4, and the black VAOd8 is the only guard on f6. So, when Black plays to release those guards, the white bishop has to both unpin the black LEOb4 (so it can mate by being a hurdle on d6) and place itself so that the unguarded square is newly guarded by the black LEO using the white bishop as a hurdle. After 1...LEb5, there is a switchback (interfering with the white bishop) leading to one of the mates from the set play.

Yes, it’s a mutate, but that is really accidental. The set play was just there. The intention was the main play after the key. I regret the multiple white PAOS and multiple black VAOS. A flawed problem, but perhaps something better may be made of it.