A Christmas Chess Puzzle

Frederic Friedel writes "Here's a nice little chess puzzle I got from Grandmaster John Nunn many years ago. It looks incredibly simple, but even the strongest players in world have been stumped by it. The problem can be stated in one simple line: A game begins with 1.e4 and ends in the fifth move with knight takes rook mate. What are the moves? If you want to read a couple of stories on it, go to Chessbase. There is a very special prize to be won if you are able to solve it -- a book signed by some of the world's top chess players, testifying that the winner is The Greatest. "

Update: 12/25 11:50 by michael : Well, I thought I figured it out, but I was wrong.

1. e4     b8-c6
2. a4     b4
3. a1-a3  c2
4. a3-d3  b4
5. g7-e2  d3++
-->

Just to clear up some confusion below, the condition is simply that a knight makes the last move of the game, which is a capture of a rook on move five (either color), and this results in checkmate for the other king. Either the knight or some other piece could be giving the check. One poster below reasons that black would be the one giving the checkmate - this is very sound reasoning. :) You just have to think outside the box.

Comments

CORRECT LINK

[Imperator]

http://www.chessbase.com/puzzle/puzzle.h tm

Re:Simple chess engine

[Rayban]

Have you ever seen the tree for chess moves? The number of possible board combinations after 5 moves is way, way more than a trillion or so. I wish I could have the number here.

What I'm curious about, however, is if it could be possible to do some sort of backwards extrapolation. Here's a bit of an idea:

(8:51pm - restate my assumptions ;))

1. There are a finite number of squares for a knight to land on in 5 moves.
2. The rook must be able to make it to one of these squares in 5 moves, so the knight can take it.
3. The king must be able to make it to a square accessible from one of these squares for a mate to occur.

Keep in mind these assumptions, as well as the fact that you might be able to castle, and you can reduce your workload dramatically.

Now... Does the program state that white knight takes black rook, or vice versa?

My thoughts

[Adar]

1. It can't be done with castling (this is fairly obvious- no way to mate with knight at the end.)

2. The mate is to the king side (the side with no queen- think of the way a knight would have to move...)

3. It's not a discover mate. That's because b1/b8 to a1/a8 takes at least four moves- which doesn't leave enough time for a relevant queen or bishop move by either side (black must move a pawn.)

4. The mate does not involve moving any rooks. There are only four positions from which a knight can mate a king on e1/e8; there isn't enough time to move a rook somewhere relevant and make sure it's not protected by any other pieces.

5. The mate is apparently by black. I say this because, if it's by white, black only has four moves- but a black mate gives black five moves, which should be the least amount you need (assuming e2-e4 is irrelevant- it's a red herring.)

That's what I was able to figure out...good luck :)

Solution

[matroid]

I have discovered a truly marvellous solution to this problem, which however this textbox is not large enough to contain.

(Now if somebody else actually publishes the solution it will at least be named after me.)


"He who takes credit for everything, is bound to get credit for something."
-My Dad

Go: The executive summary

[Our Man In Redmond]

The brief version (for those who don't care to click on the link the previous AC provided):

Go is a game played worldwide, but has the strongest "community" in the Orient, where there are Go professionals and professional Go commentators and writers (especially in Japan). The rules are fairly simple but unfortunately not simple enough to reproduce here (especially since I'm doing this from memory). Very briefly, it's played on the intersections of a 19x19 grid of lines with pieces called stones. Players alternate placing stones on the grid, attempting to capture as much territory as possible by making it impossible for the opposing player to place uncapturable stones inside the territory. A stone or group of stones is captured if it is completely surrounded by enemy stones, so if a group can't be surrounded it can't be captured. Captured stones count against a player at the end of the game, so efficiency is paramount, both in securing territory and in trying to attack it.

I remember reading a summary of a book written over 25 years ago comparing chess and go in the context of Eastern vs. Western military philosophy (this was toward the end of the Vietnam war). The author's thesis was that in chess, the object is to capture a particular piece, and a player can sacrifice as many of his pieces as necessary to capture the king. In go, the goal is not to capture particular pieces (in fact, every go stone is just as powerful as every other -- it's how groups of stones are deployed that make them weak or powerful), but to capture territory, and as I mentioned above, the more efficient you are at it, the better go player you'll be,
--