This popular Japanese number puzzle has just one easy rule: In every Row, every Column and every 3x3 sub-grid, all the numbers from 1 to 9 should appear, but only once in each row, column and sub-grid.
+------+-------+------+
| 0 0 0 | 7 0 0 | 4 0 0 |
| 0 3 0 | 0 9 0 | 0 2 0 |
| 4 0 0 | 0 0 5 | 0 0 0 |
+------+-------+------+
| 0 0 8 | 0 0 0 | 0 0 5 |
| 0 9 0 | 0 3 0 | 0 7 0 |
| 6 0 0 | 0 0 0 | 3 0 0 |
+------+-------+------+
| 0 0 0 | 4 0 0 | 0 0 6 |
| 0 7 0 | 0 2 0 | 0 9 0 |
| 0 0 5 | 0 0 8 | 0 0 0 |
+------+-------+------+

Replace the 0's with the digits required to satisfy the rule.

(In reply to re: For those who don't know... by Hugo)

I think exactly like you.

With respect to all those use computers to solve this kind of problem, I see no merit in it.

Since I don't have many time to solve them, I am solving this one too slowly. But I already put that two numbers, put all the 5"s in seconds. And stop to continue another day.

Best wishes ! 

Posted by pcbouhid on 2005-05-15 21:30:42