Play Sudoku online free

Sudoku here is the classic 9x9 number puzzle you can play in the browser: every row, column, and 3x3 box must hold the digits 1 through 9 once. Given cells are locked. You fill the empties. A wrong digit is allowed and marked in red so you can erase it and recover — the board does not block a conflict.

Three difficulties change how many clues you start with. Easy keeps about 40 to 46 given cells, Medium about 32 to 38, Hard about 26 to 30. Medium is the default. Notes mode lets you pencil candidate digits into a cell; tap the cell, then a number, to add or remove a mark. You get three free hints per puzzle. Undo stores the last 30 placements.

On a phone, tap a cell to select it, then tap 1-9 on the pad above the board. Erase clears a cell. Notes toggles pencil marks. There is no on-screen joystick. At a desk, arrows move the selection, 1-9 place a digit, 0 or Backspace erases, N toggles notes, U undoes, and P pauses. Mute stays on the shell Back/Mute row.

Score is time-based: a faster finish is worth more, and each leftover hint adds a bonus. Easy, Medium, and Hard use different bases so a hard clear can outscore a slow easy one. When the grid is full and valid, the shell posts the score and your personal best lives on the this device. The game never writes scores to localStorage. A mid-run board can come back through the shell save if you leave and return.

If you want another short session after this one, Solitaire is at /2d/casual/solitaire and Tetris is at /2d/puzzle/tetris.