Can a 2 x 2 Sudoku be the World’s Hardest Sudoku Puzzle?
We leave that for you to judge after you have solved our 6th level. We humbly that our 2 x 2 is the one of hardest Sudoku puzzles you have tried to solve. The amazing thing is that it is a 2 x 2 which in the real world is child’s play.
2 x 2 and 3 x 3 grids
Back 1, Forward 1
Rotating rows and columns