How Sudoku Works
Each puzzle starts with fixed numbers. Fill the empty squares so every row, every column, and every 3x3 box contains 1 through 9 exactly once.
Sudoku Difficulty Levels
Easy gives more starting numbers and more hints. Medium is balanced. Hard and Expert remove more clues and limit help, so leaderboard runs are tougher.
Sudoku Leaderboards
Finished puzzles can rank by score, time, and difficulty. Faster solves with fewer mistakes and fewer hints score better.