Pure logic. Minimal clutter.
A clean, lightning-fast Sudoku experience designed with developers in mind. Support for full keyboard shortcuts, smart logical hints, and auto notes.
Gameplay Tools
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How to Play Sudoku
Sudoku is a logic-based number placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids contain all of the digits from 1 to 9.
Core Constraints:
- No Row Duplicates: A digit can only appear once per row.
- No Column Duplicates: A digit can only appear once per column.
- No Block Duplicates: A digit can only appear once per 3×3 square box.
Expert Advice & Solvers:
Start by scanning rows and columns to find cells where only one number can logically fit (known as Naked Singles).
Use pencil marks to record potential candidate numbers. When a number is restricted to only one candidate cell in an entire row, column, or block, you have found a Hidden Single.
Our Smart Hint engine checks for Naked and Hidden singles dynamically to explain the exact logic, helping you become a master Sudoku player.