Planet Sudoku is a robust HTML5 Sudoku game with millions of Sudoku puzzles including Sudoku 9x9, Multi 2, Multi 4, and Samurai puzzle designs ranging from novice to expert difficulty. Choose your Sudoku design and difficulty through our advanced puzzle picker. Customize your Sudoku experience by choosing how the board looks including showing valid hints, highlighting rows, columns and boxes, and customizing backgrounds. Your progress is saved automatically in case you have to leave. Planet Sudoku is a great way of enjoying Sudoku throughout your day with so many puzzles and features to choose from!