23 March 2011

Black & White

Chess problems where one side has an overwhelming majority might not seem to be very interesting. How attractive are the following two to you?

  1Dr. Karl Fabel  
Die Schwalbe 12/1952

  2Gerhard Paul Latzel  
Schach, 1951
1st Honourable Mention

Diagram 1 features a minimal. This is a position where, apart from the king, White has only one piece. This expression was introduced by the German problemist Ado Kraemer in 1924.
The aim is to capture the black queen forcing Black into zugzwang. Obviously, the white king has to do all the work, whereas the knight controls his black adversaries on e2 and g4. He has to avoid the checks Nf6+ and Nh6+ allowing the escape of the black king. Thus, the squares d7, e8, f7, g8, h7 are taboo. On the other hand, he has to move onto a white square once (apart from g6). He has to lose a tempo, as the attempt 1. Kg7 Qh3 2. Kg6 Qh4 3. Kxg5?? shows. The nearest square to accomplish this is e6.
So, we have collected all necessary details. By now, the solution should be easy to understand.
1. Kg7! Qh3 2. Kf8 Qh4 2. - h4? forces Black to move one of his knights on move 3 thus allowing a mate in 4. 3. Ke7 Qh3 4. Kd6 Qh4 5. Ke6! Qh3 6. Ke7 Qh4 7. Kf8 Qh3 8. Kg7 Qh4 9. Kg6 Qh3 10. Kxg5 Qh4 11. Kxh4 Ne~ / Ng~ 12. Nd4 / Ne5#

Looking at diagram 2, you might think this is pretty boring to try to mate in two moves. But it's not such an easy task, though there are so many white pieces and Black has just this rook to defend!
The theme is the different ways of White to answer the checks on d6 and e5. There are four phases. First, we look at the set play (as if it were Black to move):
1. - Rxd6+ 2. Kxd6#
1. - Re5+ 2. Kxe5#
Now, we examine two tries, each invoking zugwang:
1. Nf7?
1. - Rxd6+ 2. Nxd6#
1. - Re5+ 2. Nfxe5#
1. - Rf5!
1. Qg4?
1. - Rxd6+ 2. Bxd6#
1. - Re5+ 2. Bxe5#
1. - Rd4!
Finally, there is the solution:
1. Qc8! (thr. 2. Nb6#)
1. - Rd6+ 2. cxd6#
1. - Re5+ 2. Nxe5#


HeinzK said...

Doesn't 1. ... f1=Q refute the whole mechanism?

bernoulli said...

It was a reminiscence of the previous blog post. Didn't you notice?

Comparing the piece counter and the pieces, it was evident that a black piece was missing. Moreover, it was fairly obvious that the missing piece was the black bishop on f1.

HeinzK said...

Not completely "obvious"... as there are three black bishops now :-)