Tips and strategy

• Scan for a digit that appears often on the board, such as 5, and look for where it must go in each box. Often only one cell in a box is left open.
• Check the most crowded rows, columns and boxes first. The fewer empty cells a unit has, the faster you can name the missing digits.
• Fill only digits you can prove. A wrong entry spreads errors across the grid, and the game only checks when you press Check Solution.
• Use cross-hatching. If a digit already sits in two rows of a box band, it must fall in the remaining row of that band.
• If you get stuck, switch to a different digit or a different region instead of staring at one cell. Fresh angles often reveal an easy placement.

What it exercises

Sudoku exercises logical deduction, attention to detail and working memory, since you hold several candidate digits in mind while scanning rows, columns and boxes. It also builds patience and systematic thinking, because the best solving habits involve checking one rule at a time.

Frequently asked questions

What are the rules of Sudoku?

Place the digits 1 to 9 so each appears once in every row, once in every column and once in every three-by-three box. The given numbers cannot be changed. Press Check Solution when the grid is full to verify it.

Does this Sudoku have different difficulty levels?

Yes, there are easy, medium and hard options. Switching the level loads a puzzle from that tier, and the New Puzzle control gives you another one at the same level.

Do I need to guess in Sudoku?

No. Every cell can be worked out from the numbers already on the board, so logic is enough. If two cells seem equally likely, look at another row, column or box for a clue that settles it.