alt Hacker NewsI'm 99% sure this was an invalid Sudoku puzzle.
Just before putting the 2 in here (above the pencil 6), I put in 6 and it said Mistake, so I erased it and put 2. But... why wouldn't 6 be valid there?
EDIT: As per replies, "X" Sudoku is variant with a different rule. While I saw the diagonals "highlighted" in another color, I didn't know that rule. Perhaps it could be added to the page for those unfamiliar with this non-standard Sudoku variant?
Replies
EdSchouten • yesterday at 2:58 PM
Yeah, that Sudoku puzzle has multiple valid solutions, whereas the page only seems to accept a single one.
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Because there's already another 6 on the same main diagonal. This is an "X Sudoku" puzzle, which means that each main diagonal must have all 9 different numbers.