## Minimum number of clues with 3 empty boxes?

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

### Minimum number of clues with 3 empty boxes?

It is possible to generate a sudoku puzzle with three empty boxes when the boxes are arranged in a diagonal. However there are no examples of puzzles with three empty boxes in the list of 17s. This raises the question, what is the minimum number of possible clues?
Last edited by ixsetf on Fri Oct 31, 2014 3:20 am, edited 2 times in total.
ixsetf

Posts: 50
Joined: 11 May 2014

### Re: Minimum number of clues with 3 empty boxes?

Here's one with 18 clues.

Code: Select all
`. . . . 4 9 . . .. . . . . 3 4 . .. . . . . . 1 8 .. . . . . . . 5 93 . . . . . . . 82 4 . . . . . . .. 5 9 . . . . . .. . 8 6 . . . . .. . . 1 3 . . . .`
blue

Posts: 684
Joined: 11 March 2013

### Re: Minimum number of clues with 3 empty boxes?

Hi, blue!
blue wrote:Here's one with 18 clues.

Code: Select all
`. . . . 4 9 . . .. . . . . 3 4 . .. . . . . . 1 8 .. . . . . . . 5 93 . . . . . . . 82 4 . . . . . . .. 5 9 . . . . . .. . 8 6 . . . . .. . . 1 3 . . . .`

Nice puzzle! This is double-diagonal symmetric 18-clue puzzle (did you search through its full list posted by Afmob?).

Here is my example of 24-clue puzzle, having 3 empty diagonally placed boxes.
Code: Select all
`1 9 5 7 8 . . . .2 . . 4 . . . . .4 . 7 . . . . . .6 1 . . . . . . .8 . . . . . . . 7. . . . . . . 4 8. . . . . . 2 . 5. . . . . 9 . . 1. . . . 1 3 8 9 6`
Serg
2018 Supporter

Posts: 607
Joined: 01 June 2010
Location: Russia

### Re: Minimum number of clues with 3 empty boxes?

Yes,
good old days!

a new one :
Code: Select all
` 6 9 5 1 . . . . . 2 . . 7 . . . . . 1 . . 2 . . . . . 9 2 8 . . . . . . . . . . . . . . . . . . . . . 7 3 9 . . . . . 5 . . 4 . . . . . 8 . . 3 . . . . . 9 1 2 6`

JPF
JPF
2017 Supporter

Posts: 3754
Joined: 06 December 2005
Location: Paris, France

### Re: Minimum number of clues with 3 empty boxes?

Nice shapes, Serg and JPF !

Serg wrote:This is double-diagonal symmetric 18-clue puzzle (did you search through its full list posted by Afmob?).

No, generated it on the fly. I remembered the shape, but not from where.

Here's another one with 18 clues.

Code: Select all
`. . . . . . . . .. . . . . . 4 6 1. . . 2 8 3 . . .1 6 2 . . . . . .. . . . . . . . .. . . . . . 3 9 7. . . 6 1 7 . . .5 4 3 . . . . . .. . . . . . . . .`
blue

Posts: 684
Joined: 11 March 2013