## I have a question about Sudoku

Everything about Sudoku that doesn't fit in one of the other sections

### I have a question about Sudoku

Hi, I'm new, and I have a question about Sudoku.
I know that the least numbers needed to have one solution is 17, but what is the least amount of numbers to have 2 solutions? Or the most numbers to have 2 solutions?
Sixteen

Posts: 1
Joined: 24 February 2008

Hi Sixteen, welcome to the forum.
There is no certainty about 17, just a conjecture.
See here for the answers :

16 clues :
Code: Select all
` 5 . 2 | . . . | 4 . . . . . | 7 1 . | . . 3 . . . | . . . | . . .-------+-------+------- . . . | . . 4 | 6 . . . 7 . | 2 . . | . . . . 1 . | . . . | . . .-------+-------+------- 6 . . | . . 2 | . . . . . . | . 3 . | . 1 . 4 . . | . . . | . . .`

77 clues :
Code: Select all
` 1 5 9 | 2 8 6 | 4 7 3 2 3 7 | 1 5 4 | 8 9 6 4 8 6 | 3 9 7 | 5 2 1-------+-------+------- 9 1 2 | 8 4 3 | 7 6 5 3 4 5 | . . 9 | 1 8 2 6 7 8 | 5 2 1 | 3 4 9-------+-------+------- 8 6 1 | 4 3 2 | 9 5 7 5 9 3 | . . 8 | 2 1 4 7 2 4 | 9 1 5 | 6 3 8`

These 2 puzzles have 2 solutions.

JPF
JPF
2017 Supporter

Posts: 6139
Joined: 06 December 2005
Location: Paris, France

please let us know if you find a 15 clue puzzle with just two solutions. You could then add one clue and have a 16 clue valid puzzle
ab

Posts: 451
Joined: 06 September 2005

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