## Minimum Number of Starting Digits

Programs which generate, solve, and analyze Sudoku puzzles

### Minimum Number of Starting Digits

In general, puzzles with fewer starting digits are harder
than those with more.

What is the minimum number of starting digits needed
in order to have enough information for solution.

I have several puzzles with 19 starting digits.
Here follows two such puzzles:

SODUKO 19-1
.....48..
.5...3...
6......2.
2..9...5.
....7....
.4...8..3
.3......1
...2...7.
..96.....

SODUKO 19-2
..3.....9
...1..5..
.8.4.....
..7..9..3
....6....
1..5..4..
.....7.2.
..6..3...
5.....1..

Are there puzzles with fewer starting digits?
If so, exhibit one.

Michael A. Deverin
devfam47@vtisp.com
holdout

Posts: 35
Joined: 30 August 2005
Location: Bowie, Maryland USA

If you look in the General/Puzzle forum, you'll see a huge long topic devoted to this subject. It's extremely hard to understand any of it (it is for me, anyway), but the upshot is, there are puzzles with as few as 17 clues (although they aren't symmetrical, which both your 19-cluers are. I don't think you can make symmetrical 17ers, but you might get them with 18, you'd have to read the thread).
PaulIQ164

Posts: 533
Joined: 16 July 2005