## Sunday, March 30, 2008

### More-movers

In more-movers (problems with solutions in 4 or more moves) it is sometimes easy for the solver to see the mate (to imagine the picture of the mate), but there is almost always a small obstacle, which needs a series of moves (possibly repeated) in order to be removed.

The more-mover Problem-1, that S. R. Barrett composed one and a half century ago, is solved in twelve moves. The black pawn on b2 must not be promoted, because the black may win! The repeated mechanism is simple : “pin the black pawn, check the black king”. The queen climbs the staircase c2 – c3 – d3 – d4 – e4 – e5 – f5 – f6 – g6 – g7 – h7 – h8 and, at the moment the black king is on b1, the queen slides down the column h8 – h1 and gives mate. (The presence of the three white pawn is thus explained, for it forces the queen to go at the top of the staircase).

 (Problem 13) Moutecidis Pavlos Fourth place, 2nd World Chess Compositions Contest, 1972 White plays and mates in 7 moves #7 (10+11) [ B5bB/8/2p5/Q2pS3/KS3q2/3Rp3/PP2pbps/4ks1R]

In this interesting composition, by the Greek composer Moutecidis, the single threat from Bh8 is not enough. Let us see the solution:

First Phase : Try {1.Sg4? (holds the flight f2 of the black king, threats [2.Bc3#])
1...gxh1=Q! (unpins Sf1, so it can defend by moving to d2)}

Last phase : Key 1.Κa3! (The white king unpins Sb4 and the threat is 2.Sc2++)
1...Qf8 (The black queen pins again Sb4. The mechanism unpin-pin is repeated...)
2.Kb3 Qb8
3.Bb7 Qxb7
4.Ka3 Qe7
5.Ka4 Qh4 (...but suddenly...)
6.Sg4 (...what had failed in the first phase as a try, now it is played with double threat...),
6...Qxg4 / Qxh8 (...and black is unable to parry both of them)
7.Bc3# / Sc2# .

The travel of the black queen, Qf4 – f8 – b8 – b7 – e7 – h4, forced the queen to cross over the critical square g4, and after the move 6 Sg4 the queen is not pinning Sb4 anymore. (Interesting!)

If the more-mover has a small number of moves, let us say 10, we must discover these moves. If the number of moves is greater, we must discover the mechanism that will be repeated, in order to reach mate.

The following problem, a composition of Otto - Titus Blathy, has been published many times because the stipulation is surprising, Mate in 127 moves, and also because is relatively easy to see how the mate is achieved.

 (Problem 83) Otto - Titus Blathy, “Magyar Sakkvilag”, 1930 White plays and mates in 127 moves #127 (2+14) [ 8/7p/7p/p4s1p/b3Q2p/K2p3p/p1r5/rk5s]

Key 1.Qe1+ (Who cares if this is a checking key? We must find 126 more moves!) Rc1
2.Qd2 Rc2 (We omit writing the forced moves of black: Rc1 Rc2)
3.Qd1+ 4.Qxd3+ 5.Qd1+ 6.Qd2 7.Qe1+ 8.Qe4+ 9.Qxh1+ 10.Qe4+ 11.Qe1+ 12.Qd2 13.Qd1+ 14.Qd3+ 15.Qf1+ 16.Qxf5+ 17.Qe4 (White has cleared the area, only the pawns remain in column-h, which will slowly come down...)

17...h2 18.Qe1+ 19.Qd2 20.Qd1+ 21.Qd3+ 22.Qf1+ 23.Qf5+ 24.Qe4

24...h1=Q 25.Qxh1+ 26.Qe4+ 27.Qe1+ 28.Qd2 29.Qd1+ 30.Qd3+ 31.Qf1+ 32.Qf5+ 33.Qe4 h3 (By repetition of the same mechanism we will reach the following ending)

120...h1=Q 121.Qxh1+ Rc1 122.Qh7+ Rc2 123.Qe4 Bb3 124.Qe1+ Rc1 125.Qd2 Rc2 126.Qd1+ Rc1 127.Qxb3#
(Mr. Blathy has composed problems with more moves than this!)

[This post in Greek language].