Sudoku Challenge 2

Across the 9x9 grid, Sudoku Challenge 2 strips the board down to very few given digits and leaves no built-in help to fill the gaps. Only hard settings appear here. Hard mode places no more than 6 filled cells in a 3x3 box, and expert mode drops that limit to 4. A separate challenge mode uses expert-level density with a different opening layout. Each round runs on a timer, and the final score is tied to how long the solve takes. The full board holds 81 cells, split into nine smaller 3x3 boxes by bold lines.

How to play?

Place digits from 1 to 9 into the empty cells, checking rows against columns before locking in a choice. Inside every 3x3 box, no number may appear twice, and the same rule applies across the full row and down the full column. Review the grid carefully before adding another digit, since no hints appear to correct a weak guess. Finish puzzles in hard and expert, then move on to the challenge layout with its alternate preset pattern.