Mate in 3

Given that the black king can dart to d5 and from there wriggle further to c6, seasoned solvers would be quick to suspect the key: 1.b8=N!. A quiet underpromotion — surely about as poetic an opening as a composer can hope for. But of course, the real substance of the problem lies ahead, in the play that follows. Black is in zugzwang, with five possible continuations, which can be organised into two contrasting sets of variations.

The first set is made up of the two possible moves by the bK, each giving rise to four mates:

1…Ke3 2.Be5! zz

2...b4 3.Nc4#

2...g5 3.Nxf5#

2...fxg4 3.Rxe4#

2...exd3 3.Bd4#

1…Kd5 2.e3! zz

2...b4 3.Bc4#

2...g5 3.Rxf5#

2...fxg4 3.Bxe4#

2...exd3 3.Rd4#

Notice something neat: the mates after the same set of Black’s second moves — 2...b4, g5, fxg4, and exd3 — change between the two variations, even though they all land on the same squares: c4, f5, e4, and d4, in that order.

The second set consists of moves by three different black pawns, each yielding a pair of mates:

1…b4 2.Ne6+!

2...Ke3 3.Nc4#

2...Kd5 3.Bc4#

1…g5 2.Nxb5+!

2...Ke3 3.Nxf5#

2...Kd5 3.Rxf5#

1…fxg4 2.Nc6+!

2...Ke3 3.Rxe4#

2...Kd5 3.Bxe4#

Here, in response to the same pair of Black’s second moves — 2...Ke3 and 2...Kd5 — the mates differ across the three variations, forming a 3x2 Zagoruiko.

A rich mix, overall — harmonious and tightly composed, by the fine duo of Slovakian composers!