Sudoku Classic

Sudoku Classic brings the timeless number puzzle to your browser without any fuss. A 9x9 grid, nine 3x3 boxes, and the numbers 1 through 9 — the rules haven't changed, and they don't need to. Every row, column, and box must contain each number exactly once. That constraint is deceptively simple, yet it produces an enormous range of puzzle complexity.

Difficulty options mean you can pick something manageable on a lunch break or sit down with a genuinely demanding grid that requires real patience. Hints are available if reasoning hits a wall, and an undo button lets you backtrack without restarting entirely — both welcome features when a puzzle starts unraveling.

The interface stays out of the way. Cells are clear, number entry is straightforward, and nothing distracts from the logic work itself. Whether you solve sudoku regularly or haven't tried one in years, the format is immediately familiar and the challenge remains honest.