How to Play Sudoku: A Beginner's Guide
Sudoku looks like a maths game, but you never add or multiply anything. It is a logic puzzle about placing the numbers 1 to 9 so that none repeats where it should not. Here is how to get started.
The rules
The board is a 9x9 grid, split into nine smaller 3x3 boxes. Every row, every column and every box must contain each number from 1 to 9 exactly once. Some squares are already filled in; your job is to fill the rest. A well-made puzzle can always be solved by logic, so you never need to guess.
Start by scanning
Pick a number that already appears many times, such as 5. Look at each box that does not have a 5 yet and check which squares are blocked by a 5 in the same row or column. Often only one square is left, and that is where the 5 goes. Repeat with other numbers until the easy squares are done.
Use notes and look for singles
When no obvious moves remain, write small notes in each empty square for the numbers that could still fit. If a square has only one possible number, it is a naked single. If a number can only fit in one square of a row, column or box, it is a hidden single. These two ideas solve most easy and medium puzzles.
Mistakes to avoid
Do not fill squares by guessing; one wrong number can spoil the whole grid. Check each new number against its row, column and box. If you get stuck, take a short break and look at the board again with fresh eyes.