You are handed a grid partly filled with digits and must complete it using pure logic, never guesswork. Each row, each column, and each of the nine boxes must contain the numbers one through nine exactly once. The given clues constrain everything, so every cell has a single correct answer.
How to play Sudoku
- Select an empty cell on the 9x9 grid
- Enter a digit from 1 to 9 that does not repeat in its row, column, or box
- Use pencil notes to track candidates for tricky cells
- Fill every cell correctly to complete the puzzle
Tips & strategy
- Scan for rows, columns, or boxes that already hold eight numbers
- Pencil in candidates for each cell to spot forced placements
- Work the easiest deductions first to open up harder regions
Controls: Click a cell, type 1-9
Sudoku — FAQ
Is guessing ever needed in Sudoku?
A well-formed puzzle always has one solution reachable by logic alone, so guessing is never required.
What do the pencil marks do?
They let you jot possible candidates in a cell without committing, which helps you reason through tougher spots.
