TIPS AND TRICKS

Become a sudoku master

Cryptic crosswords aren’t the only challenges you’ll find in the Telegraph puzzle pages. Sudoku puzzles masquerade as simple time-fillers, but can challenge the grey matter of even an expert in number games.

To recap on the basics: each row, column and 3x3 box of cells must contain one of the numbers 1 to 9. If you find yourself putting a number in a cell that already exists in its horizontal or vertical line, stop. That road only leads to despair.

When tackling a sudoku puzzle, the first thing you should do is scan the rows and columns for numbers that are obviously missing. And, when you manage to start filling in numbers, be methodical and check how putting them in will impact the rest of the grid.

Once the scanning process draws to its natural conclusion, a logical process of analysis has to be undertaken. This is helped by marking the possible numbers for each cell. Imagine each cell is a 3x3 grid of the numbers 1 to 9, and mark a dot in the relevant space to denote the potential number that might be its resident.

Logic puzzles that require the solver to assume potential answers require a technique called Ariadne’s thread; also known as “backtracking”. By leaving a trail of evidence, if the route is incorrect then you can easily return the way you came without becoming disorientated. It should be possible to solve all of our sudoku puzzles by logic alone, but if you do make a guess, make sure you can find your way back if you have to!