Sudoku
Guide
English

Your First Sudoku

Learn the rules in three minutes, start a game and find your first number.

On this page
  1. There is only one rule
  2. Counting rows, columns and boxes
  3. Start a game
  4. Find your first number
  5. What happens when you make a mistake
  6. Next steps

There is only one rule

The grid has 9 rows and 9 columns, and is split into nine 3 × 3 boxes. Some numbers are given. Fill in the empty cells so that:

  • every row (across) contains 1 to 9 exactly once;
  • every column (down) contains 1 to 9 exactly once;
  • every box contains 1 to 9 exactly once.
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The shaded cells are one row, one column and one box. Each of them must hold 1 to 9 exactly once, with no repeats and no gaps.

The numbers are just nine symbols. There is no arithmetic. Every puzzle here has exactly one solution and can be solved by logic alone, so you never need to guess.

Counting rows, columns and boxes

Rows are counted from the top, columns from the left. The small numbers beside the diagrams are the row and column numbers. Boxes are counted from the top left to the bottom right: boxes 1 to 3 across the top, 4 to 6 in the middle and 7 to 9 along the bottom.

The in-game hints and this guide use the same names, such as "row 3, column 7" or "box 5".

Start a game

  1. Press "Play now" on the home page, or go straight to the game.
  2. Choose a difficulty. For your first game, pick Easy: many numbers are given, so the next move is easy to spot.
  3. Press "Start game". Puzzles are generated on the spot, so every game is different.

To play the same puzzle as everyone else, choose the Daily challenge. See Difficulty, daily challenge and stats.

Find your first number

The most useful method is to look at one number at a time. Pick a number that already appears many times, then find a box that does not have it yet:

  1. That number cannot appear again in the rows and columns it already sits in. Imagine those rows and columns "crossing out" cells as they pass through the box.
  2. If only one empty cell in the box is left uncrossed, that cell is the answer.
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Look at box 4: the 2s outside the box cross out its rows and columns, leaving only one cell for 2.

This technique is called a hidden single. Easy and Medium puzzles can be solved from start to finish with it and the naked single. When one number runs out of moves, move on to the next number.

What happens when you make a mistake

The default mistake check is "Limit 3": a number that does not match the solution turns red, and the game ends after 3 mistakes. When it ends you can choose "Second chance" and keep playing, but that game will not count toward your best time.

If you would rather not be told, change the mistake check to "Highlight" or "Off" in the settings. See Controls and settings.

Next steps

Up nextControls and Settings →
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