Sudoku
Choose Easy, Medium, Hard, or Expert. Difficulty follows the solving techniques a puzzle needs. Clues stay locked. Tap a number or use the keyboard. Notes are pencil marks. Check marks mistakes without giving the answer. Hint shows the next logical step. The timer is optional, and this browser keeps your place.
Arrow keys move. Number keys fill the selected square. N turns notes on or off. Backspace erases. Ctrl+Z undoes.
Puzzle engine: sudokuJS by Jonas Ohlsson, MIT License. jQuery is included locally under the MIT License. License notes