Intro

Sudoku is a simple but tricky puzzle in which the player aims to fill in a square grid, following only a few simple rules.

An unsolved sudoku puzzle looks like this:

And ends up like this:




The three simple rules which drive the puzzle are:

– in each column the numbers 1 to 9 each have to appear once.

– in each row the numbers 1 to 9 each have to appear once.

– in each 3×3 block (indicated by the thick black lines) the numbers 1 to 9 each have to appear once.




When you start a puzzle, a few squares will already have been filled in for you. From these you can deduce information about what must be in one of the blank squares – and then another, and another…

On to Tutorial 1