The New Sudoku Players' Forum

[Drjsguo]

I discovered a logic-Sudoku named Mudan Rainbow Sudoku that has only eleven digits. Is this the ultimate minimum-digits limit for a 9X9 Sudoku puzzle?

www.chinasudoku.com

Who has seen one less than that before? Please tell us.

Drjsguo 3/3/2007

[udosuk]

I've posted a couple with eight:

http://forum.enjoysudoku.com/viewtopic.php?t=4566

The absolute minimum is zero, but that's another story...

[Drjsguo]

Very interesting. Thanks!

I was thinking the minimum digits required could be 8. I never thought zero is the answer. Could you give us more info?

[Drjsguo]

After think it over again, I finally get your point. I agree with you “zero” is the minimum digit for logic Sudoku, if all numbers are restricted to certain rules. In that case, since all 81 numbers are fixed. Without any number showing we are still be able to get the answer.

Thanks for your answer.

[udosuk]

Yes, you got the concept why zero is possible...

Here is an example:

Code: Select all

. . . | . . . | . . .
. . . | . . . | . . .
. . . | . . . | . . .
------+-------+------
. . . | . . . | . . .
. . . | . . . | . . .
. . . | . . . | . . .
------+-------+------
. . . | . . . | . . .
. . . | . . . | . . .
. . . | . . . | . . .

Place the digits in this Sudoku such that the resulting 81 digit number formed by stringing the rows one after the other in order from top to bottom is minimum.

PS: Despite being a Chinese speaker, I never had a seriously strong interest in your website... But I guess it's a nice one, so keep up the good work!

[Drjsguo]

Nice tip. Thanks.