🎮 Sudoku

What is Sudoku? 🔢
Sudoku is a logic-based number puzzle where you fill a 9×9 grid with digits from 1 to 9. Every row, every column, and each 3×3 block (box) must contain each number exactly once. With no math tricks or guesswork required, the fun is in deducing the only valid moves.

A short history

The modern Sudoku most people play today was first published in the late 1970s under the name Number Place. It is widely credited to Howard Garns, a U.S.-based puzzle creator (American architect), and it first appeared in puzzle books published by Dell Magazines in 1979.

Sudoku’s name and popularity exploded in Japan. The puzzle was introduced there in 1984 by Maki Kaji of the Japanese puzzle company Nikoli. The term Sudoku comes from Japanese and relates to the idea of keeping numbers “single” in each place.

Objective

Complete the entire grid so that each 1–9 appears once in every row, column, and 3×3 block. When all cells are filled correctly, you win.

How to play 🎮

• Start - Click Play to begin a new Sudoku puzzle (and continue an unfinished one if your browser has saved progress).
• Choose difficulty - Pick Easy, Medium, or Hard depending on how many starting clues you get.
• Fill the grid - Place digits so they don’t repeat within the same row, column, or 3×3 block.
• Use notes (pencil marks) - Mark possible candidates in empty squares to keep track of what can go where.
• Work from constraints - If a cell can only take one number based on its row/column/block, that move is usually the best next step.
• Check your progress - Keep solving until every square is correctly filled.

Sudoku tips 🧠

• Look for “singles” - Scan for cells where only one number is possible.
• Use candidate tracking - Notes help you avoid forgetting possibilities and make future deductions faster.
• Clean up the obvious first - Finishing small areas often reveals new forced moves elsewhere.
• Be systematic - Instead of scanning randomly, check one row, one column, and one block at a time.
• Reduce options for the next step - Many wins come from removing one candidate that then forces a chain of placements.

About the game - A browser-based Sudoku puzzle experience with multiple difficulty levels, optional notes/pencil-marking, and a save-and-continue style of play so you can return to your puzzle anytime.