The wandering king December 31, 2007
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Some problems are just fun – in the same way jigsaw puzzles or knitting are fun. In the following the challenge is to work out a plan and then count the number of moves required to execute it.

Otto Wurzburg, 1919

Only the white king moves. How many legal
moves does it take to get him to the square f4?

Black makes no moves at all. The only piece that moves during the entire problem is the white king. But all its moves must be legal. Of course the king may not move onto a guarded square or capture a guarded piece. Make sure you count every step. The solution to this problem is a number, specifying exactly how many moves are required to reach the goal.

Incidentally, if you are using ChessBase or Fritz you can enter the moves of such problems by entering null moves for one side. This is done by pressing Ctrl-Alt-0 (zero on your num pad). So in the above problem you move the white king to a4, then press Ctrl-Alt-0, move it to a5, Ctrl-Alt-0, to a6, etc. Oops, have we revealed too much of the solution?

Otto Wurzburg, 1875–1951, was one of the most imaginative American problem composers, the nephew of the most prolific of them all, William A. Shinkman (1847–1933). Doubtlessly inspired by him, young Otto started composing at the age of twelve, as chess historian Edward Winter has discovered.

Feedback on our previous problems

Richard Stein, Berkeley, CA, USA
I am a longtime chess enthusiast who discovered your site about two years ago in February. I was on board for your Christmas puzzle set last year and I think the formula you used was a good one, with easy puzzles early on in the week and hard-hitting from about day five on. That seems to me to be the best way to satisfy this diverse puzzle-solving field.

Eric Jones, Ravenna, Ohio USA
I wouldn't worry about people complaining. As far as the problems being too easy or too hard, I would say they are neither. Of course, the first few were a little easy, but regardless of that they are still fun to do. I would word them the way you want to word them. If they are easy (such as the series helpmate in four), then say it is. It isn't your fault that somebody can't solve an easy problem. In terms of playing strength I am not as strong as the guy who can't solve the helpmate in four. That doesn't mean that it isn't overall easy. It is. The helpmate in eight was definitely a lot harder, and eventually I solved it. You were right by the way, it is very nice the way it is solved, going back and forth with the knight and bishop to keep the 1st rank blocked from the white rook until the mate at the end. The series helpmate in 21 is a totally different story. I can't figure out what to promote to. I have constructed the possible final mating positions (I'm pretty sure there are a couple) but for the life of me don't know how or when to take the white pawns and with what. However these puzzles are great fun. Who cares if it says it is easy or not. The essence of problem-solving in my opinion is solving the problem, not the difficulty of it. I don't think anybody could be disappointed after correctly solving an "easy" problem. Isn't it a good thing that it was "easy" for you?

Or Cohen, Israel
I consider myself an average solver, thus, it was a sheer joy for me – being able to solve today's puzzle (Jacob Mintz, series helpmate in 21 – correct solution given).

Steve, Bass, Plano, Tx
I enjoyed reading the discussion in Puzzle #3 about different readers' views about the levels of puzzle difficulty. My only comment is that I'm very suprised you did not take advantage of the writers' names (Paul and Piotr) to state that in terms of difficulty you "don't want to rob Piotr to pay Paul"

Josh H. Hamilton, Canada
I need to know, in the series helpmate, can Black allow his king to be in check while he is making his set of moves? Also: for the December 27th puzzle, can you make sure that the helpmate is after 21 moves and not 22. I'm probably wrong but it's driving me insane so I thought I would ask.

Neither king can ever be in check during the moves of a series helpmate, except in one case: on the last move Black can put the white king into check, after which White makes his checkmating move, which of course would have to take his king out of check.

A surprising number of readers asked us about the Jacob Mintz puzzle, and whether it did not require 22 moves to solve. Initially we were baffled (by so many parallel queries) but then realised that these readers were executing a different mate that is only possible in 22 moves. However, the version we published is correct, the problem can be solved in 21 moves!

Noam D. Elkies, Cambridge, Mass
Am I right to guess that the Bartel-Kniest series helpmate originally had a "twin" with the black king at h1 instead of g1? That too has a unique solution in four (which unlike the solution of the Kg1 diagram depends on the exact positions of the White pieces for its uniqueness!).

Indeed that is the case, as our resident problem guru John Nunn confirmed. "As originally published in Feenschach, the problem did indeed have a twin," he wrote. "You should mention the other half of the problem, without which it loses most of its appeal." Unfortunately the twin was not given in the problem collection which we were using. We present the two problems here together.

E. Bartel and A.H. Kniest, 1965
s
Series helpmate in four:
a: diagram
b: bKg1–>h1

So Black moves four times in a row and then White plays one move to mate him. In one case the black king is on g1, as in the diagram above, in the twin problem the black king is on h1. The solutions are quite different.

Technical note: unfortunately some intellectually or emotionally starved soul is spamming our puzzle account with hundreds of automatically dispatched emails. Please do not write for a day or so, until we stop the disruptive tream of messages – or the perpetrator discovers that he has a life, however bland it may seem to be.

Frederic Friedel