Official Sudoku is a simple to learn number-based grid game - fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. There is no maths involved. The grid has numbers, but nothing has to add up to anything else. You solve the puzzle with reasoning and logic. It's fun. It's challenging. It's addictive! Solving time is typically from 10 to 30 minutes, depending on your skill and experience. Each volume 10 puzzles ranging from Easy to Fiendish. And if you're desperate, we take pity on you and hand out clues - but only one hint at a time.