Goal
Fill in the empty cells with numbers 1-9 to complete the puzzle.
How to Play
- Tap an empty cell to select it
- Enter a number using the keypad below
- Switch to memo mode to note candidate numbers
Row & Column Rule
The same number cannot appear twice in the same row or column
Box Rule
The same number cannot appear twice within a bold-bordered box
Completed Example
- Each row must contain 1-9 exactly once.
- Each column must contain 1-9 exactly once.
- Each bold-bordered box must contain 1-9 exactly once.
Tip
- Start with rows or boxes that have the most filled cells
- Use memo mode to note down candidate numbers
- If only one empty cell remains in a row, the missing number is the answer
Sudoku trains working memory and logical reasoning simultaneously. Numerical logic tasks have been shown to improve executive function.
- Ferreira et al. (2015) - Numerical Logic and Executive Function
- Grabbe (2011) - Sudoku and Cognitive Abilities