Leonid Kubbel
An intensive rendering of a simple theme. Solvers might like to consider
if the problem would be improved by replacing the black pawn at b3 with
a black bishop at b1.
1.Bh8 places Black in zugzwang, and each of six defences closes a line which prevents a promotion from
defeating White’s continuation. 1...Sg3 2.Sh3 threat 3.Sg5 (2...g1Q?); 1...Sf2 2.Se2 threat 3.Sd4
(2...g1Q?); 1...b2 2.Sb3 threat 3.Sd4 (2...a1Q?); 1...Sb2 2.S×b3 threat 3.Sd4 (2...a1Q?); 1...Sc5 2.Qb2 threat
3.Qe5; 2...Sd3, Sd7 3.Qxb3 (2...c1Q+?); 1...Sc3 2.Qd2 threat 3.Qd7; 2...Sd5 3.Qxd5 (2…c1Q+?); 1...e3 2.Qxe3.
If the black pawn at b3 was replaced by a black bishop at b1 the repeated continuation would be avoided, and
all of the defences would be played by the knights. Such things are just a matter of opinion, but the aesthetic
gain seems to me worthwhile. Use of the rook is a rather expensive way to guard f7, and if the above change was
made it could be replaced by a white pawn at g6 and a black pawn at g7, but the gain in economy would be offset
by the loss of the charming bishop-to-the-corner key.
Dafydd Johnston: Even though replacing the pawn on b3 with a black bishop on b1 reduces the number of
thematic lines, I think it would improve this problem because then each black move would be answered by a
unique reply and mate.
Jacob Hoover: A mighty fine example of line play.
Guy Meissonnier: What a nice and subtle key!