3
2
1
7
8
4
9
4
9
6
4
1
8
6
2
9
6
8
9
4
5
1
7
8
4
2
3
3
9
6
5
4
4
8
6
Sudoku is listed as a recommended mental exercise in several cognitive rehabilitation programs for TBI (traumatic brain injury) patients.
Sudoku is listed as a recommended mental exercise in several cognitive rehabilitation programs for TBI (traumatic brain injury) patients.
Finnish mathematician Arto Inkala created what is widely considered the world's hardest Sudoku in 2012.
Finnish mathematician Arto Inkala created what is widely considered the world's hardest Sudoku in 2012.