Sudoku FAQ

What is sudoku?

Sudoku is a logic puzzle, consisting of a nine by nine grid of squares. Each row, column, and three by three of the grid contains the numbers one to nine- but only once. A true sudoku grid has only one unique solution, and can be solved without guesswork.

What does sudoku mean?

The name Sudoku is apparently an abbreviation for Suji wa dokushinsha ni kagiru. The classic translation apparently means "numeral(s) limited to a single person". This probably refers to the fact that only one of each digit can appear in a row, column or box.

Sudoku or su doku?

There doesn't seem to be a definitive 'correct' name, however virtually everywhere seems to use 'sudoku'. The exception is The Times newspaper in the UK, which uses 'su doku'.

How do you play sudoku?

You are provided with an incomplete grid, and must figure out what number goes where until you have completed the puzzle to form a valid sudoku grid.

What makes one puzzle more difficult or easier than another?

In general, puzzles where you are given less starting numbers are harder than those where there are several, as you need to put more effort in to get started and there is often only one avenue you can pursue at a time (one possible number to find). Also, with easier puzzles you can work out a number easily as there is only one candidate, with harder puzzles you may have to perform more complex logic.