This online Sudoku brand provides free 9x9 puzzles, a feature-rich game interface, and learning tools for players at different skill levels. Its puzzle library offers a broad range of difficulties, from kindergarten, very easy, and elementary through high school, college, and graduate levels, as well as an Expert Area for exceptionally challenging games. A Daily Sudoku page supplies a new puzzle for each difficulty level every day.

Players can also use a blank grid to enter and solve puzzles found elsewhere. The interface supports candidate notes, cell highlighting, undo and redo, automatic candidate entry, mistake and rule-violation checks, and saving unfinished games. Puzzles can be selected by number or generated at random.

For help and instruction, the site offers a Sudoku solver with both instant solutions and step-by-step explanations. Its smart solver demonstrates the logic and techniques used at each stage, while the learning section presents a range of solving methods with examples.