# Is it possible to position all chess pieces on the board such that all pieces defend at least one piece and attack at least one piece?

Is it possible to position all chess pieces on the board such that all pieces defend at least one piece and attack at least one piece?

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-1 Irrelevant to play. – aramis May 8 '11 at 7:25
+1 interesting question for all chess fans and good tactical exercise! – user545 May 8 '11 at 13:03
When you say "pieces," do you mean just the pieces, or the pawns as well? – BlueRaja - Danny Pflughoeft May 8 '11 at 16:25
I mean the pawns as well. I think doing it that way makes it more interesting and complicated... :P – El'endia Starman May 8 '11 at 17:40
This reminds me of a computer problem, How do place X (I forgot the number) queens on the board so they don't "attack" each other? – Tom Au Jun 9 '11 at 20:59

Yes, and it's not particularly hard to do. Here's one solution.

I found this by placing the pawns first (because they are much more limited in their attack/defence potential), and then adding the pieces one at a time. Using this simple manual approach, it took about 15 minutes to find a solution. As an added constraint, I avoided placing the kings in check.

There are undoubtedly many alternative arrangements that would also work. It would be quite straightforward to write a computer program to search for valid configurations. A simple brute-force backtracking algorithm would probably suffice.

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+1. But I'd move the R on e8 to c8 instead. On e8 it's not really "defending" anything, since the K can't be "defended" (defending is preventing something from being taken because of retaliation, which of course doesn't apply to the K). But then the black K isn't defending anything, so move it to e7 instead. (Did I miss something?) – msh210 Jan 18 '12 at 19:06
@msh210 - On c8, the black rook wouldn't be attacking anything, so I don't think that's a valid solution. Regarding defense of the king, I agree, but bear in mind this whole position is already very artificial (although I tried to make the pawn positions vaguely real-looking). – ire_and_curses Jan 18 '12 at 19:29
Hm, so maybe put the R on e7 instead of e8. – msh210 Jan 18 '12 at 19:31
Yes, that would work. @Dave DuPlantis - do you think you could redo the image to move the black rook on e8 to e7 (I'm not sure how you generated it in the first place)? – ire_and_curses Jan 18 '12 at 19:36
@ire, I used this page, the one I linked to in the chess tag wiki. If there are similar sites, we might want to update the wiki or perhaps find a more visible spot for them? – Dave DuPlantis Jan 18 '12 at 22:04