Sudoku - Ad-Free Number Puzzle

No ads, no sign-ups. Just Sudoku. Instead of simply revealing the answer, we explain the logic behind each step.

Don't just check the answer. Understand why it belongs there.

Discover the logic behind each move with step-by-step hints based on your current board. From Singles and Pairs to X-Wing and Swordfish, explore a variety of solving techniques. See exactly which cells each hint applies to and the cells that support its reasoning, right on the board.

Make repetitive input faster and easier with drag-to-select, locked number input, and smart pencil notes.

Every puzzle is verified to have a unique solution and to be solvable through logic alone, without guessing. Choose from three difficulty levels: Easy, Normal, and Hard.

Key Features

• Step-by-step hints that explain the logic behind each move using your current board
• Drag-to-select multiple cells and locked number input
• Smart pencil notes with candidate conflict prevention and automatic cleanup
• Undo, erase, and remaining number counts
• Highlighting for the selected number and the related row, column, and box
• Optional three-mistake limit
• Per-cell scoring based on solving time
• Resume unfinished games
• Cumulative statistics by difficulty and weekly records
• Light and dark modes
• Available in English, Korean, and Japanese

Start playing instantly with no ads or account required. Your game progress and completed puzzle records are saved on your device.