The kinky art of Selfmate December 28, 2006
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Puzzle 4

In a selfmate, White is to trying to commit suicide; in other words, he is trying to force Black to deliver mate. Black is doing everything in his power to avoid mating White.

Selfmate in four moves

In the above position, White moves first and must force Black to deliver mate at the latest by Black’s fourth move. The basic idea is to compel Black to give a discovered mate along the first rank, but at the moment this idea doesn’t work because the a1-rook is under attack from the bishop on h8. There are actually four variations, but all involve the same idea so once you have found one, you shouldn’t have any trouble with the others.

John Nunn

For those of you not familiar with the selfmate, you can read about this ancient art and solve some elementary puzzles here.

The solutions to all puzzles will be published at the end of the week (after January 1st).
Some clues and feedback may be published during our Christmas puzzle week.

Some feedback from our readers

Freeman Ng, Oakland, California, USA
At first, I thought the flash of insight that might be required to solve this puzzle [#1] was to realize that the knight doesn't necessarily have to be the piece that administers the mate, and so wasted a lot of time trying out discovered mate scenarios. After I gave up on that approach, I found the straightforward configuration almost on my first try. Initially I was a bit disappointed that the solution wasn't "lateral" enough. However, after thinking some more about the problem, I see that there is indeed a clever twist: You'd think that once a mating net was worked out, it could be applied to any of the three possible squares where the black king would receive a check from the knight – and indeed, this is why I was initially sure that this couldn't be the right path to a unique solution. But it turns out that one square works, for the pleasingly counterintuitive reason that only that option gives the white queen enough space to cover the squares it needs to. Nice!

Manikumar, Chennai, India
Well! A good yet easy problem [#1]. The point is to give maximum mobility to the black king in the center, which is unexpected.

Yuen Chi Ho, Hong Kong, China
Here's a brief plan on my thinking process for problem one: (1) Using proof by contradiction, we deduce that the fourth piece must be white piece, or else White cannot have enough pieces to checkmate. (2) Doing an exhaustive check of all cases of discovered attacks shows that a checkmate in this way is impossible. So the checkmate must be delivered by the white knight itself. (3) We know the white knight uses one of its controlling square to check the black king, so it can only control at most one additional square next to the black king. Three more squares next to the black king can be controlled by the white king. The fourth piece must control at least four squares next to the king, which means the fourth piece must be a white queen. (4) Design the placing of each piece from the analysis above and the answer is out.

Ron Fenton, Yellow Springs, USA
What a pleasure it is to once again, leave one's troubles behind for a week and be awed by the limitless beauty of chess. After #2, I returned to give #1 the study it stubbornly demanded, but it wasn't long before I found myself re-reading the problem for a third time – hoping in vain to find a semantic explanation for what I had just proved for the second time, was an impossible task. Happy ending: it's slightly past midnight here and I finally got it! I can't wait to see what's next – and to think, it's only a few hours away! Thank you Chessbase, and thank you GM Nunn, for sharing your genius and your encyclopedic knowledge of problem composition with us once again. Merry Christmas indeed!

Hui Shao, Beijing, China
I'm a student from Beijing (Peking). Thank you for giving our chess fans interesting puzzles from Christmas day to the day before New Year's Day. Vrolijk Kerstfeest en een Gelukkig Nieuwjaar!
Merry Chrismas & Happy New Year! :)

Rui Pereira, Lisboa, Portugal
Regarding your polyglot "Christmas greeting", I was quite puzzled to find out that you were able to include such exotic languages as "Cornish", "Cree", "Samoan" or "Somali", and even the nonexistent "Brazilian", but couldn't get to include "Portuguese", which is spoken by more than 200 million people all around the world (even if most of those people are Brazilian, the name of the language is still "Portuguese"). Bom Natal e Feliz Ano Novo!

Richard Bunner, Honolulu, USA
I almost gave up [on Puzzle 1], thinking that there had to be a trick (even though you mentioned "no tricks"). Thanks for the present!

Paul Lillebo, Asheville, NC, USA
An unclarity in John Nunn's Christmas Day puzzle: it reads, "there were only four pieces on the board". To English-speaking chessplayers (such as GM Nunn), the word "pieces" normally refers to what other languages call "officers", that is, it does not include pawns. But if this is meant, there could be any number of pawns on the board, in addition to the "four pieces". The more probable interpretation is that Nunn is using "pieces" to mean "chessmen", so that only four chessmen, whether pawns or otherwise, are on the board. A third way of reading the sentence, though ungrammatical, is as "there was naught but four pieces on the board", although here again we have to wonder about the meaning of "pieces". – No, I haven't yet solved the puzzle, under any of the alternatives.

Kevin Spiteri, Marsaxlokk, Malta
After solving the problem, I wrote a small program to generate problems like the puzzle (mate after a knight move, total four pieces). There are plenty of puzzles, but the only puzzles with a unique solution are the one you published plus reflected, rotated and shifted versions of it. There are 328 different knight moves which might lead to mate with four pieces on the board, but 312 have non-unique solutions, with the largest number of solutions being 179, e.g., for Na4-b6.

Matt DeElena, Lakewood, CO USA
Thank you for such an enjoyable puzzle [#1]. I was determined to solve this one! Especially since I was unable to solve any of them last year. Thank you, and Merry Christmas!

Szymon Rudowski, Brooklyn, NY USA
Hey guys, what about some season's greetings in Polish? Well, anyway, Merry Christmas (or Wesolych Swiat) to you!

Alain Gilbert, San Francisco, CA
The multilingual Christmas card is lovely, but as a minor correction: In Afrikaans, "Happy New Year" is "gelukkige nuwejaar", not "gelukkige nieuwejaar", which sounds like a Dutch construction.

Juha Patosalmi, Helsinki, Finland
First of all, thank you again for the puzzles that wake the brain up after a couple of days of christmas-dining at the in-laws. The first one was a nice starter of a hopefully challenging series. Considering what was special about that problem was the fact, that the black king was in the middle of the board, rather than where one would expect it to be (in the corner). An additional difficulty was that there was actually no tricks involved here (discovered checks, captures with the knight, etc.), which took first 15 minutes of my attention.

Martin Sims, Palmerston North, New Zealand
I have a question about the main diagram in puzzle two which has driven me crazy for over a decade! How do you do a diagram without kings please?

In ChessBase: set up a position with kings, use "Edit - Copy position" and insert the diagram in Photoshop or another graphic program. Move the kings in ChessBase and do a second capture. Cut out the empty squares in the second diagram and paste them in the first. Takes about two minutes total. – Frederic Friedel

Leo Kuiper, Leiden, The Netherlands
Great puzzles so far! I have solved all of them I think. I have enjoyed your puzzles and look forward to he rest! Thanks for the pleasure!!

Ljubica Lazarevic, UK
With regards to the suicide (giveaway) chess puzzle, Mr. Nunn has incorrectly stated that king promotions are not allowed. This is incorrect. One can not only promote to a king, but can have several monarchs on the board if desired. Kings have no special position as they do in regular chess.

Marcin Kasperski, Poland
There are two variants of 'loose your pieces' chess. The one you describe is usually called 'suicide'. The other one, called 'losers', differs – the king is not usual piece, you must defend against checks, and being mated is also a win. Suicide is more popular, losers is a bit strange, but the difference is worth mentioning to avoid confusion....

Arie Haenel, Jerusalem, Israel
As always I enjoy the original puzzles of the end of the year. Thanks. PS: No prize this year?

Colin Everett, Colwyn Bay, UK
Very nice first puzzle. I'm guessing this is one of the easy ones... By the way, any chance we can have the answers to last year's Christmas Contest Puzzles?

Sorry, no prize competition this year. And the solutions to last year's problems, together with a somewhat tortured explanation for the delay, will be provided at the end of this puzzle week.