Friday, March 28, 2008

Two-movers (1)

Two-movers are called the problems that have two-move solutions.
The sequence of moves is W – B – W (white plays the key – black plays a defense – white gives mate) in orthodox two-movers. The moves have an alternative naming : W1 first white move, B1 first black move, W2 second white move, etc..

The sequence of moves is B – W – B – W in heterodox helpmate two-movers.

The sequence of moves is W – B – W – B in heterodox selfmate two-movers.

The two-mover in the next diagram-10 is a composition by Kapralos Dimitris and Siotis Nikos. The problem took the first prize in the ‘orthodox two-movers category’ in the chess problem composition contest, which was organized by the Chess Federation of Bulgaria for the 1300 years anniversary since the formation of the Bulgarian state. (In the Greek team also participated the composers Zappas Byron, Martoudis Pantelis, Moutecidis Pavlos, Fougiaxis Harry. The team gathered 2 first prizes, 1 third prize and 3 commendations).

(Problem 10)
D. Kapralos – N. Siotis,
First Prize, International contest ”Bulgaria 1300”, 1983
(Set play). White plays and mates in 2 moves
* #2 (10+8)

First Phase : (*) (set play)
1...Kc5 2.Se7# (The move of the knight has opened simultaneously three white lines).

Second Phase : 1.Sd3? (trial game, [2.e5#])
1...Rxf7! 2.e5+ Kxd5!

Third Phase : 1.Se6? (trial game, [2.e5#])
1...exd2! 2.e5+ Kxd5! (The black king takes the white knight but, before that, five white controls of the square d5 are annihilated).

Fourth Phase : Key 1.e5! (triple threat [2.Qc2# / Se6# / Sd3#]),
1...Kc5 2.Qc2# (the mate of the set play has been changed),
1...Rxf7 2.Se6# (the defense of the second phase is met by the try of the third phase),
1...exd2 2.Sd3# (the defense of the third phase is met by the try of the second phase).

The problem contains the Fleck theme, named after the Hungarian composer Ferenc Fleck:

Theme Fleck : The key introduces multiple threat, at least triple. In each variation the defense of the black leaves only one threat valid.

(Update 15/02/2008) : Mr Fougiaxis Harry, International Master, elucidates:
To be exact, we have here the theme pseudo-Fleck, since some of the black moves do not separate the white threats. Theme Fleck demands "n" threats to exist (at least 3) which are separated by equal in number black moves, without duals in the variations.
Interesting version of the theme is the
Theme Karlström-Fleck : The key introduces multiple threat, at least triple. The defense of the black separates the threats, and in each variation only one remains valid. There is at least one black move that is defense for all threats of the key, but allows some other mate.

[This Post in Greek language]

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