The New Sudoku Players' Forum

[mith]

Code: Select all

+-------+-------+-------+
| . . . | . . 9 | 8 . . |
| . . . | . . . | . . . |
| . . . | . . 7 | . . . |
+-------+-------+-------+
| . . . | 8 . 6 | . 9 . |
| . . 7 | . . 5 | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+
| 8 . . | . 4 . | 3 . 2 |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+
.....98................7......8.6.9...7..5............8...4.3.2.................. anti-king (diagonally adjacent cells cannot contain the same digit)

A quick search didn't turn up any results for minimal given count for this variant, but here's one with 12. (Not hard)

[mith]

Aha, found the Mathimagics thread under "SudokuDP": sudokudp-diagonal-pairs-t35036.html Looks like 12 was the best known as of 2018?

[Mathimagics]

Yes, I remember observing that 12-clues was fairly easy to find ...

But you can be the first to find an 11-clue, I think ...

[mith]

I've got 11 down to 42 solutions (remove the 2 from the grid below). But I happened to get it that low looking for something else:

Code: Select all

+-------+-------+-------+
| . . . | . . 9 | 8 . . |
| . . . | . . . | . . . |
| . 7 . | . . 6 | . . . |
+-------+-------+-------+
| . . . | . . . | . 9 . |
| . . 6 | . . . | 5 . . |
| 8 . . | . . . | . . 4 |
+-------+-------+-------+
| . . . | 5 . . | 3 . . |
| 2 . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+
.....98............7...6..........9...6...5..8.......4...5..3..2................. (anti-king... OR anti-knight)

[mith]

We have some examples of 11 givens with 2 solutions (initially with only 7 distinct digits, but now one with 8 distinct and 12 cells left to disambiguate). Getting close...

[mith]

Code: Select all

+-------+-------+-------+
| . . . | . . 9 | . . . |
| . . . | . . 8 | . . . |
| . . . | . . 7 | . . . |
+-------+-------+-------+
| . . . | . . . | . 9 . |
| . . 7 | . . . | . . . |
| . 6 . | . . . | . . . |
+-------+-------+-------+
| . . . | . 5 . | 4 . . |
| . . 3 | . . . | 2 . . |
| . . . | 6 . . | . . . |
+-------+-------+-------+
.....9........8........7..........9...7.......6...........5.4....3...2.....6.....  anti-king