The ' simple logic' approach to sudoku requires only visual analysis and goes something like this: Can the 2 go in the empty square? It can't, because box 2 already has a 2, and it can only have one of each number. To fill the empty square at row 3, column 4, we're going to have to look at column 4, row 3 and box 2. Take a look at the empty square at row 3, column 4 (3,4), and the row and box that interact with it: So where does each number go? To find out, we need to look at the rows and boxes that interact with column 4. But we can't just put them anywhere - each number has a specific location in the puzzle's answer. In order to have one and only one of each digit from 1 to 9, we're going to have to provide column 4 with its 2, its 6 and its 7. If you can solve an easy puzzle, you can solve a hard one - it'll just take you more time. Let's walk our way through the easy puzzle above to get a feel for the process.

The best way to learn the art of sudoku is by working through a puzzle. (Michael Mepham, puzzle creator for London's Daily Telegraph, rates his puzzles as either Gentle, Moderate, Tough or Diabolical.) An easy puzzle gives you enough numbers placed in enough strategic positions to allow you to find the answer using fairly simple logic.

Sudoku has several levels of difficulty, from easy to very hard, based on how many numbers you get to start with and where those numbers are positioned. Here's an example of a real sudoku puzzle from Michael Mepham's 'Book of Sudoku 3':Ī sudoku puzzle has some 'clues' filled in. A sudoku puzzle already has some of the numbers filled in, and it's your job to figure out where the rest of the numbers go. Of course, starting with a blank grid wouldn't make it much of a challenge. So if you were to start with a blank grid and fill in the numbers for row 1, column 2 and box 4 according to the sudoku rules, it might look something like this: It's the interaction between the rows, columns and boxes that tells you where the numbers need to go. The goal of sudoku is to fill each nine-square row, each nine-square column and each nine-square box with the numbers 1 through 9, with each number used once and only once in each section. You've got three sections to think about: rows, columns and boxes. The basis of the sudoku game is a nine-by-nine grid. Instead of 1 through 9, you could use the first nine letters of the alphabet or a set of nine symbols, and it would be the same game. Sudoku (or su doku) is a game of numbers - specifically, the numbers 1 through 9 - but it really isn't about math.

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