The object of sudoku is to complete the puzzle so that the numbers 1 to 9 appear in each row, column and 3×3 box.
The same number must never appear twice in the same row, column or box.
The numbers can appear in any order.
Don’t worry about the diagonals – they are not used in sudoku.
Each puzzle starts with some numbers already filled in to get you started. These numbers are called “givens”. You can’t change the given numbers.
Sudoku puzzles always have only one solution.
Although sudoku is typically played on a 9×9 grid, different sizes of sudoku are available. For example, sudoku for kids is often played on a 4×4 grid. Some advanced players like to challenge themselves with monster sudoku played on a 12×12 grid using the numbers 1 to 9 and the letters A,B and C.
The video below, designed for beginners, demonstrates the basic methods used to solve a sudoku puzzle.