Very long mates December 29, 2005
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Before we come to our subject of the day we revisit, briefly, the historical problem form of the selfmate. Thr problems we provided in our previous column were new to many readers, and fascinating to even more. Here's a brief encore.

E. Hasselkus, Schach-Express 1948

Selfmate in seven moves

Remember: in the above position the task is for White to play and force the uncooperative black side to deliver mate. The problem has a very nice humorous solution, and is easy enough for us not to have to provide any hints. Incidentally all solutions will be provided at the end of the puzzle week.

Very long mate problems

The most common form of chess problem is the direct mate, and more specifically the mate in two moves. Many tens of thousands of such "two-movers" have been composed, and they are the ones you most commonly find in newspapers and chess columns. Mates in three are also fairly popular, though many find them more daunting. Problems with mates in four or more moves are less common and hardly ever encountered in non-specialist publications.

So what about problems that require you to find fifty and more accurate moves? Forget it, we hear you chant. No way I'm ever going to be able to solve something like that. Well, give it a try, we promise to be gentle.

Note: in order to make it easier for you to work with a chess program we are giving you position descriptions in text format. If you are using Fritz or ChessBase you can click on "File – New – Position setup" (or simply press 'S') to enter a new position, then copy the ASCII description below the diagram and use "Paste ASCII" in the Setup screen to enter the position with one click.

Karl Fabel, Die Schwalbe 1938

White mates in how many moves?
wKf1,Nf6,Bh1,h4,Pf2,g5/bKf3,Nh8,Bh3,Rg2,Pd4,d5,d6,d7,f4,f5,f7,g6

In the above problem by one of the all-time great unorthodox problem composers (in one of the all-time great unorthodox problem chess magazines) the number of moves to mate was specified. But of course no help was given. We are going to discuss the problem in some detail, so in order to leave a small challenge we do not tell you how many moves to mate.

Let us take a look (please) at the above position. The black king is immobilised, and has no square that it can move to. The black rook is pinned and also cannot move, nor can the knight or any of the black pawns on the kingside. Only the black bishop can move, back and forth, achieving nothing. And of course the pawns on the d-file.

You may have noticed a few other things about the position. If the black bishop is not on h3 White has a mate in one: BxRg2#. So the black bishop must stay in place as long as the white king is on f1. The white king can move away to lose a move, e.g. with Ke1-d2-d1-e1-f1, with black simply shuffling his bishop between h3 and g4. After that we have the same position as in the diagram, and Black is in zugzwang. He cannot move his bishop to g4 any more, since BxR# would follow. So he is forced to move a pawn.

An idea comes to us: So why doesn't White simply march his king to the d-file, capture all the black pawns, do the little triangulation d2-d1-e1-f1 and then have black in deadly zugzwang. Because the white king must also guard the square e2, otherwise its black counterpart will escape from the trap it is in. That means that the white king can only move up to d3. But it can perform the move-losing manoeuvre to force a pawn onto that square: 1.Ke1 Bg4 2.Kd2 Bh3 3.Kd1 Bg4 4.Ke1 Bh3 5.Kf1 and now (in exactly the same position as in the diagram above) it is black to move. Since ...Bg4 is not possible Black must play 5...d3.

Jawohl, the pawn is within range of the white king and can be captured: 6.Ke1 Bg4 7.Kd2 Bh3 8.Kxd3 Bg4. But now it can go no further, so 9.Kd2 Bh3 10.Kd1! Bg4 11.Ke1 Bh3 12.Kf1 and once again Black is in zugzwang.

Well, that is all we are going to tell you for the moment. Your task is now to work out how White proceeds, forcing the black pawns to advance, capturing them, and then at last bringing the king back to f1 with the black bishop on h3. Black will not have a waiting move – he will have to move his bishop and allow the mate on g2. Please make a note of exactly how many moves White needs to achieve this goal, i.e. how many moves it is to mate in the above position.

Here are some other delightful problems by Karl Fabel. We will encounter more of his fabulous ideas in the next installment of our Christmas Puzzle week.

Frederic Friedel