PlaySudoku.us
Hard · Puzzle #4
6
8
3
5
2
4
1
1
9
4
3
7
5
7
1
8
3
6
7
9
1
4
1
5
3
6
4
"The only impossible journey is the one you never begin." — Tony Robbins
"The only impossible journey is the one you never begin." — Tony Robbins
The number of essentially different Sudoku grids (accounting for symmetry) is 5,472,730,538 — about 5.5 billion.
The number of essentially different Sudoku grids (accounting for symmetry) is 5,472,730,538 — about 5.5 billion.