Saturday, February 27, 2016

A selfmate, with strip-tease.

Selfmate are the compositions where White plays first and forces Black to mate, while Black tries to avoid it.

Theme Strip-tease : One by one some pieces are removed from the chessboard, leaving a new problem to be solved.

This theme, Stip-tease, is contained in Problem-777 (see here) which has got a distinction in the World Congress of Bern.

Today we will see an easy selfmate. Black has a light-squared Bishop who can mate the cornered in h1 white king, and the matter is how can we empty the diagonal from the pieces that block (direct obstacles wQb7, bPc6, bKe4) or can inhibit the mate (possible obstacles wPe2, wRh5, wRg4, wBa4) the mate.

Manolas Emmanuel (GRE)

b3S3/1Qp5/2p5/2B4R/B1P1kPR1/8/3PPp1p/5SbK (12 + 7)
Twins a) diagram,
b) = a) -wPc4,
c) = b) -wRg4

1.Be3! (the obstacle wPe2 is gone) Bxb7 (the obstacle wQb7 is gone)
2.Bxc6+ (the obstacle bPc6 is gone) Bxc6 (the obstacle wBa4 is gone)
3.f5+ (the obstacle wRh5 is gone) Ke5+
4.Re4+ Kxe4 (the obstacle wRg4 is gone)
5.d3+ Ke5# (the last obstacle bKd4 is gone)

b) -wPc4
1.Qxc7! Bb7 2.Bxc6+ Bxc6 3.f5+ Kd5 4.f6+ Ke6+ 5.Re4+ Bxe4#

c) -wPc4, -wRg4
1.Qb1+! Kxf4 2.Qe4+ Kxe4 3.Be3 c5 / Bb7 4.B(x)c6+ Bxc6 5.Re5+ Kxe5#

In these three twin compositions, White loses a pawn and a rook, one after the other.
In each occasion, sacrificing pieces and threatening the bK, White forces Black to mate in 5 moves.