The selfblock is one of the simplest of chess problem themes, shown
here in a fine task setting.
A brilliant key, 1.Se3, threatens 2.Sc4 and allows
the black king to capture both rooks, with matching mates at
either end of the diagonal - 1...Kxd6 2.b8Q and
1...Kxf4 2.Qh2. Black can selfblock three times on each
flight square. 1...Rxd6 2.Rf5, 1...Sxd6 2.Sg4, 1...exd6
2.Rxe4, and 1...Rxf4 2.Re6, 1...Sxf4 2.Qd4, 1...gxf4
2.Rd5. There is one by-play variation 1...Sb2 2.Sg4.
Jacob Hoover: A lovely puzzle with a very pleasing
self-block theme. I found the by-play a little unimpressive,
though.
I think Jacob is being a little hard on the composer. Three
selfblocks on each of two flight squares following a key which
gives both flights is a considerable achievement. By-play is
usually an afterthought, either arising naturally from the
matrix or added to force potential mating moves which are not
used in the main theme. I think that the composer would have
been perfectly justified if he had chosen to add a black pawn at
b2 to eliminate the knight defence, leaving his 8 thematic
defences.