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View Full Version : OT - Chesspiece puzzle

QuikSand
03-10-2003, 09:55 AM
As opposed to a "chess puzzle" (along the lines of "mate in two") this is simply a chesspiece puzzle. The setting doesn't involve an actual game of chess, just knowledge of how the pieces work.

Using a standard 8x8 chessboard, and with the traditional move of a knight (two spaces in one orthogonal direction, then one perpendicular space either way... I presume you get the idea), here's the puzzle:

What is the smallest number of knights that can be placed on a chessboard such that every single space is either occupied by or threatened by a knight?

[edit for poor grammar only]
HornedFrog Purple
03-10-2003, 10:00 AM
I will let it sit for a while instead.... sorry
rlfreeze
03-10-2003, 12:03 PM
Are you able to move multiple knights at the same time?

EDIT: Nevermind
QuikSand
03-10-2003, 12:47 PM
HFP... five minutes seems pretty quick for this puzzle. Did you "solve" it in that time, or have you seen this before?

Either way, thanks for not posting a super-quick spoiler...
HornedFrog Purple
03-10-2003, 12:53 PM
Both. It was actually in a chess training book I have, but it had been a long time since I had done it. It was more memory recollection than anything. I just never get your other ones, chess problems I enjoy. :)

I actually came up with two variations with the same number of pieces if my scribblings on a notepad are right. There may be more.
albionmoonlight
03-10-2003, 01:54 PM
I got 16 by dividing the board into 4 squares and showing that you can fill each square with 4 knights. However, I am sure that one with more time to fiddle than I have could cut that down a bit. Wish that I had more time to look at this one. . . .
albionmoonlight
03-10-2003, 03:08 PM
looked at it a couple more ways and still get stuck on 16. There has got to be a better answer, though. . .
Maple Leafs
03-10-2003, 03:35 PM
Just curious: Are there any chess experts on this forum who'd be interested in a challenging chess problem?
Airhog
03-10-2003, 03:54 PM
well ryche and Mattjones4heisman are really good players. I would enjoy a challenging problem myself.
Maple Leafs
03-10-2003, 04:04 PM
Originally posted by Airhog
well ryche and Mattjones4heisman are really good players. I would enjoy a challenging problem myself. I have one in mind that was reasonably straightforward, yet extremely difficult (to the point that grandmasters have failed to solve it). I'll dig around and see if I can find it.
Craptacular
03-10-2003, 04:11 PM
For the original puzzle, I got 16 for a couple of obvious patterns, but now I found one with 12.
AnalBumCover
03-10-2003, 07:37 PM
I got 12.
QuikSand
03-10-2003, 07:45 PM
12 is the best possible answer. Good work, ABC. Care to illustrate?
AnalBumCover
03-10-2003, 07:51 PM
Originally posted by QuikSand
12 is the best possible answer. Good work, ABC. Care to illustrate?

Black square is occupied by a knight. Red square indicates threatened by knight.

http://www.geocities.com/robordona/chess.gif

Hope I'm right!
ABC
AnalBumCover
03-10-2003, 07:52 PM
can you all see the above picture???
RPI-Fan
03-10-2003, 08:25 PM
No - but on a related note, did anyone watch the chess matches on ESPN over the past couple of weeks?

I found them suprisingly enjoyable.
Craptacular
03-10-2003, 08:31 PM
I think I made it on QS's ignore list. ;)
AnalBumCover
03-10-2003, 11:26 PM
Originally posted by Craptacular
I think I made it on QS's ignore list. ;)

That's okay C-Tac, I'm sure you got the same answer I did. :)

For those who can't seem to view my above pic, I've attached it.
QuikSand
03-11-2003, 05:03 AM
Originally posted by Craptacular
I think I made it on QS's ignore list.

Did anyone hear something?

(Sorry 'bout that... my attention span apparently only made it halfway through your answer. Nice job to you too, C.)