## Chess Sudoku

For fans of Killer Sudoku, Samurai Sudoku and other variants

### Chess Sudoku

This Sudoku-like puzzle uses chess pieces instead of numbers.

Starting with this position, fill the board with two complete chess sets of white and black pieces (2 kings, 2 queens, 4 bishops, 4 knights, 4 rooks, and 16 pawns of each color, 64 pieces total) in such a way that:

• No king is in check. (Intervening pieces block horizontal, vertical, and diagonal checks, of course.)
• There are no pawns on the first or eighth ranks. (In chess, ranks (rows) are numbered from bottom up, so the first rank is at the bottom, eighth rank at the top.)
• There are exactly two white pawns and exactly two black pawns on each file (column), with each of the two white pawns occupying a lower-numbered rank than each of the two black pawns.
• There are at most five white pawns on any rank, and at most five black pawns on any rank.
• All pieces on the first and second ranks are white, and all pieces on the seventh and eighth ranks are black.
• Of the four white bishops, two are on light squares and two are on dark squares, and similarly for the four black bishops.
• No white rook is on the same rank or file as any black rook or black queen, and no black rook is on the same rank or file as any white rook or white queen.
• No white bishop is on the same diagonal as any black bishop or black queen, and no black bishop is on the same diagonal as any white bishop or white queen.
• No white queen is on the same rank, file, or diagonal as any black queen.
• No white knight is a knight’s move away from any black knight.
Unless I’ve messed up, this puzzle has one, and only one, solution.

Bill Smythe
Smythe Dakota

Posts: 564
Joined: 11 February 2006

### Re: Chess Sudoku

Hi Bill,

Don't even think of posting a solution too soon!!! Give at least another week, PLEASE!!!!!

I'm trying to have some time this week to solve it!!!

tarek

Posts: 3752
Joined: 05 January 2006

### Re: Chess Sudoku

It's not as hard as it looks. I posted this same puzzle on the chess forums (http://www.uschess.org/forums/viewtopic.php?f=23&t=19846) and got a response and solution (via PM) within hours.

But yes, I'll wait several days. Or you can post a progress report every day or two.

Bill Smythe
Smythe Dakota

Posts: 564
Joined: 11 February 2006

### Re: Chess Sudoku

Is anybody ready for a hint or two?

Bill Smythe
Smythe Dakota

Posts: 564
Joined: 11 February 2006

### Re: Chess Sudoku

A hint would be great!!!

tarek

Posts: 3752
Joined: 05 January 2006

### Re: Chess Sudoku

Start with the pawns on the c- and f-files. Then go for the pawns on the b- and d-files.

Files in chess are lettered left to right, a through h.

Bill Smythe
Smythe Dakota

Posts: 564
Joined: 11 February 2006

### Re: Chess Sudoku

No free time since my last post ... Not sure when I'm going to have any!!!!

tarek

Posts: 3752
Joined: 05 January 2006

### Re: Chess Sudoku

I will give it a try this night
Vaynard

Posts: 2
Joined: 26 June 2014