HOW TO SOLVE SUDOKU
Sudoku rules and solving techniques: scanning, naked singles, hidden singles, pencil marks, naked pairs and box-line reduction — a step-by-step beginner guide.
Sudoku rules
A sudoku is a 9×9 grid split into nine 3×3 boxes. Fill the empty cells so that every row, every column and every 3×3 box contains each digit from 1 to 9 exactly once. A proper sudoku has one solution, and every puzzle in YOZGAMES Sudoku does — logic is enough, no guessing needed.
1. Scanning
Pick a digit, say 5, and mentally block out the rows and columns of every 5 on the grid. If a box has only one cell left where 5 can go, write it in.
2. Naked single
Look at one cell: which digits already appear in its row, column and box? If only one digit remains, that is the answer.
3. Hidden single
If a digit has only one possible cell in a row, column or box, it goes there — even if that cell has other candidates.
4. Pencil marks
On harder puzzles, note the candidates in each empty cell. In YOZGAMES Sudoku the ✏️ Notes button (or N) toggles notes, and placing a correct digit clears it from the notes in the same row, column and box.
5. Naked pair
If two cells in a row (or column, or box) share exactly the same two candidates, say {3,7}, those digits belong to those cells; remove 3 and 7 from the other cells of that row.
6. Box-line reduction
If a digit's candidates inside one box all sit on a single row, the digit must be in that row within the box; remove it from the rest of the row. The same works for columns.
Common mistakes
- Guessing leads to chains of errors; take notes instead.
- Stale notes: clear old candidates as you place digits.
- Sticking to one technique: when scanning stalls, move on to candidates and pairs.
In YOZGAMES Sudoku
- Three levels: Easy (40 clues), Medium (32), Hard (26), plus the same Daily Sudoku for everyone.
- 3 hints per puzzle, undo and erase; a digit that clashes in its row, column or box turns red.
- Your score depends on level, time, mistakes and hints; progress saves automatically.
Play sudoku free — no download, no sign-up, on phone and desktop.