# Knights of the Square Sudoku Table

 8  .  . | .  .  . | .  .  6
.  .  4 | .  .  . | .  .  .
.  .  . | .  .  . | 9  1  .
---------+---------+--------
.  .  . | .  2  . | .  .  .
.  .  9 | 3  .  . | .  .  .
.  .  . | .  .  . | .  .  .
---------+---------+--------
.  .  . | 9  .  7 | .  .  .
9  .  . | 6  3  . | 4  .  .
.  .  . | .  .  . | 1  .  .

• Normal sudoku rules apply.
• Long diagonals contain only unique values.
• If A is a box-center, and A and B are a knight's move apart, then A and B ought to be different.

A knight's move constitutes going up/down by two followed by going left/right by one, or going up/down by one followed by going left/right by two:

. . B . B . .
. B . . . B .
. . . A . . .
. B . . . B .
. . B . B . .

• Does "diagonals" mean just the two long diagonals, or every line at 45 degrees? [EDITED to add:] Duh, must be the former since there are two diagonally-adjacent 1s in the grid already. – Gareth McCaughan Dec 10 '19 at 22:35
• It looks like the 9s in R2C4 and R4C5 contradict the pseudo-knight move restriction. Is that intended? – HTM Dec 10 '19 at 22:38
• The same with 5 at the top right. – Moti Dec 11 '19 at 1:25
• I believe this is unsolvable. I've tried twice to solve it deterministically, both times resulting in contradictions. Are you able to check that a solution exists satisfying the conditions? – Matthew Jensen Dec 11 '19 at 4:01
• The puzzle should be solvable now. I updated the puzzle itself and the instructions. Thanks for your feedback. – Joris Schellekens Dec 11 '19 at 10:01