This problem (from Ideal-Mate Review,1997) is a series helpmate in 25. In other words, Black makes 25 moves in order to reach a position in which White can play a mating move.
It becomes apparent that the only way to achieve mate is by Black blocking his potential flight squares at d7, e7, f7, f6 and f5. This will entail using each of his five potential blockers; all four Pawns will have to promote. The solution therefore comprises a wonderfully precise interlocking sequence in which every element falls into place with move-by-move exactitude (a requirement of the problem being considered sound). The f5 square must be blocked first (otherwise moving the P from g5 to g4 would give check); and you will find that there are reasons why each of the other bPs, once freed up, have to complete their manoeuvres before the next stage in the process can be undertaken. And it also transpires that we have to make one of each of the possible promotions (i.e. once to N/B/R/Q): ‘Allumwandlung’ (or ‘AUW’ for short) in problemists’ parlance – 1.a1N 2.Nc2…4.Nf5 5.g4…8.g1Q 9.Qgg5 10.Qf6 11.g5…15.g1R 16.Rg7 17.Re7 18.Qhf7 19.h5…23.h1B 24.Bc6 25.Bd7 d5#.
If you like that one, you may like to have a go at another Sphicas series helpmate, this time in 30 moves, from Ideal-Mate Review, 1995 –
This time we don’t get AUW, but what we do get is four ‘Excelsiors’, i.e., each of the four black Pawns is moving the whole way to promotion from its starting square. And this time there are six blocking squares to be occupied (as well as a black piece to be sacrificed at g5), so this is a longer, more complex move sequence, whose logic you will enjoy unravelling – 1.a5…5.a1B 6.Bg7 7.Kf6 8.Be6 9.d5…13.d1R 14.Rd7 15.Rf7 16.Ne7 17c5…21.c1B 22.Bg5 23.Rb5 24.Re5 25.b5…29.b1B 30.Bf5 hxg5#.
These two problems qualified for inclusion in Ideal-Mate Review because one of their achievements is that in each the final position satisfies the criteria of an ‘ideal mate’: every unit on the board contributes to the mate either by blocking or by guarding a potential flight square, and there is nothing superfluous in the way in which each potential flight is nullified (i.e., no square that is guarded as well as blocked). From experience I know how challenging it is to find settings in which you don’t have to add any extraneous material to the board in order to exclude unwanted alternative solutions (‘cooks’)!
Christopher holds the Grandmaster title for Chess Problem Composition and uses his skills to write a regular column for the Bristol Chess Times. He is also a longterm Horfield Chess Club player (where he is acting secretary).