Sudoku

A NUMBER GRID BUILT AROUND LOGIC

Sudoku is a classic number puzzle where you complete a 9×9 grid using the numbers 1 through 9. Each row, column, and 3×3 box must contain every number without repeats, turning a simple-looking board into a problem of careful deduction.

The puzzle starts with several numbers already placed as clues. Use them to work out which values can fit into the empty spaces. Different difficulty levels can change how much information you have at the start, making Sudoku suitable for both beginners and players who want tougher logic problems.

HOW TO SOLVE THE SUDOKU GRID

Start with a row, column, or 3×3 box that has many numbers already filled in. Look for the missing values and check where each one can legally go.

• Check the three rules: A number cannot appear twice in the same row, column, or 3×3 box.
• Find an obvious placement: If an empty cell has only one possible number, enter it immediately.
• Compare possible positions: When a number has several candidates, check the surrounding rows, columns, and boxes to remove impossible choices.
• Use notes when needed: Mark potential numbers in difficult cells instead of making an uncertain move.
• Keep updating the board: Every correct number creates another clue, which can reveal placements that were hidden before.

Use Elimination Before Guessing

A strong Sudoku strategy is to eliminate numbers rather than guess them. For example, if a 7 already appears in the relevant row and box, that value cannot occupy the cell. Continue checking the connected areas until only one valid choice remains.

More advanced puzzles may require techniques such as hidden singles or pairs, where the position of possible numbers reveals information that is not immediately obvious.

Controls

• Mouse - Select a cell
• Number buttons / Keyboard - Enter a number
• Notes - Mark possible values

MORE LOGIC PUZZLES TO TRY

• Futoshiki Unlimited
• 2048
• Pips Unlimited