Sudoku

Overview

The classic logic puzzle: fill a 9x9 grid with digits 1 through 9 so that no number repeats in any row, column, or 3x3 box. Use the given clue numbers to deduce the rest. Three difficulty levels let you choose your challenge -- from relaxing easy puzzles to brain-bending hard ones.

Key Features

• Puzzle generation across 3 difficulty levels: easy, medium, and hard
• Note-taking mode to pencil in candidate numbers per cell
• Automatic conflict highlighting for duplicate numbers
• Undo feature to revert mistakes
• Completion time tracking to challenge your personal best

How to Use

1. Choose a difficulty to generate a new puzzle
2. Click or tap an empty cell, then enter a number from 1 to 9
3. Toggle note mode to pencil in multiple candidate numbers per cell
4. Fill every cell correctly following the rules to complete the puzzle!

Tips

• Start with cells or groups that have the fewest candidates remaining
• Use the note feature liberally to narrow down possibilities
• Focus on digits that already appear frequently -- they're easier to place since fewer spots remain
• When stuck, move to a different area of the grid. New deductions often unlock progress elsewhere

FAQ

What's the difference between difficulty levels?

The number of given clue digits differs. Easy has more clues for straightforward deduction, while hard has fewer, potentially requiring advanced solving techniques.

How does the note feature work?

Activate note mode and enter a number to pencil it in as a small candidate in the cell. Press the same number again to remove it.

Does the game tell me if I enter a wrong number?

Duplicate numbers in the same row, column, or 3x3 box are highlighted as conflicts. However, a number that doesn't conflict but still isn't the solution won't be flagged.