- 22 Jun '05 09:45I tried and solved my first (easy) Sudoku puzzle recently. It set me to wondering however: What is fewest number of initial entries into a 9 x 9 sudoku grid that permit such a puzzle to be solved? I suspect the number can be formally arrived at, but I don't know how. Any takers?

Aiden - 22 Jun '05 10:41On the sudoku site the puzzles there show either 3 or 4 numbers

in each sub grid. So your only possiblity is 1 or 2 as smaller, not

much of a range. 1 you could eliminate as allowing many solutions

so the idea is to figure out if 2 in each grid could be set up

to have only one solution, I think not. I think with 2 in each grid you

have many more solutions so it looks to me like 3 and 4 are the

minimum already. - 22 Jun '05 19:07 / 1 edit+ 3 + + + + 9 + +

6 + + 4 + + + + +

+ + + + + + 7 + +

+ 7 + 2 9 + + + +

+ + + 3 + + + 6 +

+ + + + + + + 4 +

4 + + + + 5 + 8 +

+ + + + 7 + 3 + +

+ + 1 + + + + + +

OK I doubt this will work. But there is a 17 number setup with a unique solution. No 16 numbers setups with unique solutions have been discovered but they haven't been shown not to exist.

EDIT: Well it worked kind of. - 22 Jun '05 20:09

The answer to that is, of course, the answer to the Soduku thing added to the number of months of the year and a lot of bad luck.*Originally posted by The Plumber***Oh, you meant 17 was the answer to the Soduku thing, I was thinking of Life, the Universe, and Everything.**

nevermind....

That's how I got to the answer to the Soduku thing

42 = 12 + 13 + X

X = 17 - 22 Jun '05 22:14

well that blows my 3 and 4 thing. The puzzle I saw on the sudoku*Originally posted by XanthosNZ***+ 3 + + + + 9 + +**

6 + + 4 + + + + +

+ + + + + + 7 + +

+ 7 + 2 9 + + + +

+ + + 3 + + + 6 +

+ + + + + + + 4 +

4 + + + + 5 + 8 +

+ + + + 7 + 3 + +

+ + 1 + + + + ...[text shortened]... have been discovered but they haven't been shown not to exist.

EDIT: Well it worked kind of.

site had 6 3's and 3 4's (30) It just seemed to allow more

solutions if you had less occupied squares.

So the key is the *position* in the squares. - 28 Jun '05 22:16

They've just started doing these in my local newspaper. The ones I've seen have 3 or 4 entries in SOME subsquares, but definitely not every subsquare.*Originally posted by sonhouse***well that blows my 3 and 4 thing. The puzzle I saw on the sudoku**

site had 6 3's and 3 4's (30) It just seemed to allow more

solutions if you had less occupied squares.

So the key is the *position* in the squares.