Sudoku is a logic puzzle where you fill a 9x9 grid with the digits 1 to 9. Every puzzle here has exactly one solution and comes in three difficulty levels, so you can always solve it by logic alone, without guessing.
How to play
Every row, every column and every bold-outlined 3x3 box must contain each digit 1-9 exactly once.
Tap an empty cell, then use the number buttons below (or keys 1-9) to enter a digit. Entering the same digit again clears it.
Turn on Notes to jot down small candidate digits. When you place a digit, matching notes in its row, column and box are removed automatically.
Duplicate digits in a row, column or box are shown in red.
Stuck? The Hint button fills one cell with the correct digit: the selected cell if it is empty or wrong, otherwise a random cell that is not correct yet. You get 3 hints per puzzle and each one adds 30 seconds to your time.
Fill every cell correctly to win. Your time is recorded per difficulty, and an unfinished puzzle is saved so you can continue later.
Tips
Start with rows, columns and boxes that are almost full; a unit missing just one or two digits is the easiest entry point.
If a digit can go in only one cell of a box, that cell is the answer.
When stuck, switch on Notes and write candidates for each cell. A cell with a single candidate will show up.
Selecting a digit highlights every identical digit on the board, which helps you spot where it still has to go.
