Sudoku

Preparing the board…

Rules and controls

Fill each row, column and 3×3 box with the digits 1–9, each exactly once. Given numbers cannot be changed. Select an empty cell and use the keypad or type a number; arrow keys move between cells. Notes record candidates; Erase clears a value or notes. Conflicts are marked when a digit repeats in a row, column or box.

Reveal cell provides the answer for your selected cell and marks this attempt assisted. Undo reverses edits. Easy puzzles use singles; Medium adds locked candidates or naked pairs; Hard requires hidden pairs or X-Wing without guessing. Every puzzle is checked for exactly one solution.