Thursday, February 16, 2012

An Elementary Chess Problem

Can you solve this problem?

The White King has been knocked off the board. To find the solution, you must place it back on the board on its correct square.

There is only one correct square, and when the King returns to the board it will be a legal position.

I was shown this wonderful position by chess player and friend Colin Dougherty in Tallahassee, Florida. I meditated on it for a week, but was unable to solve it.

I eventually came to the conclusion that it is not solvable, but I was wrong. In fact, there is a very elemental solution. There are no tricks.

I have also shown this problem to five other strong masters, including two players that are rated over 2450. None of these masters were able to find the solution. However, Boylston Chess Federation board member Dan Schmidt solved the problem in less than five minutes. So far, he is the only person to solve it.

If you can solve it, you can join Dan and achieve a small piece of chess immortality. If you can't, then you can join me and the other masters who failed!

Good luck. :)


Ken said...

This looks and smells like an old Raymond Smullyan problem from his first book of retrograde analysis. I had the second, but I think I gave it away years ago.

Someone showed me such a problem (probably this same one) back in the early 80's, and I can still remember the key to the solution. I think I could have sleazily, I mean, easily, beaten Dan.


dfan said...

Yeah, the reason I was able to solve it relatively quickly is that I have seen a lot of retrograde analysis problems in the past, so I was already familiar with the bag of tricks you use for these sorts of problems.

Daniel Franke said...

I figured it out. Here's the answer base64 encoded to prevent spoilage (ROT-13 doesn't quite cut it for obscuring chess notation):


CTheil said...

Very good! Congratulations Daniel.