SudokuguroWhat are the basic Sudoku rules?
Fill every empty cell with a number from 1 to 9. Each row, column, and 3x3 box must contain every number exactly once.
Sudoku Basics
Sudoku Rules
Review the complete rules for classic 9x9 Sudoku: numbers 1 through 9, row limits, column limits, 3x3 box limits, and clean solving habits.
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Key Takeaways
- A classic Sudoku board has 81 cells arranged in nine rows, nine columns, and nine 3x3 boxes.
- Each row, column, and 3x3 box must contain the numbers 1 through 9 exactly once.
- Sudoku is solved by logic and elimination, not by arithmetic.
Can a Sudoku puzzle have more than one answer?
A fair classic Sudoku puzzle should have one solution. Sudokuguro validates playable boards for a unique solution.
The 9x9 Board
A standard Sudoku puzzle uses a 9x9 board split into nine smaller 3x3 boxes. Some numbers are already placed when the puzzle starts.
The player's job is to fill the empty cells so the completed board obeys the same rule in every row, every column, and every box.
Rows, Columns, and Boxes
A row is horizontal, a column is vertical, and a 3x3 box is one of the nine square regions.
When checking a possible placement, look in all three places before entering the number.
Common Rule Mistakes
New players sometimes check only the row or only the box. A legal move must pass all three checks at the same time.
Another common mistake is treating Sudoku like a math puzzle. The numbers only need to fit the placement rules.
FAQ
Do Sudoku numbers need to add up to anything?
No. Sudoku uses numbers as symbols. The rule is placement: each row, column, and 3x3 box needs the digits 1 through 9 exactly once.
Can I repeat a number if it is far away on the board?
Yes, as long as the repeated number is not in the same row, column, or 3x3 box.