9️⃣ Sudoku
🧩 Puzzle · 0 playsSudoku
The classic 9×9 logic puzzle with four difficulty levels.
About Sudoku
Fill the 9×9 grid so every row, every column, and every 3×3 box contains the digits 1 through 9 exactly once. Every puzzle is freshly generated with a unique solution, from relaxed Easy boards to brutal Expert ones. Includes pencil notes, mistake checking, and a timer.
How to Play
Tap an empty cell, then tap a number to fill it in. Every row, column and 3×3 box must contain 1–9 with no repeats. Use notes mode to pencil in candidates. Three mistakes ends the game on hard modes.
💡 Tips & Strategy
Start every puzzle with a scan for forced cells: pick a number that appears often and trace its rows and columns through each 3×3 box — often only one cell in a box can legally hold it. Working 1 through 9 this way solves most easy and medium puzzles outright.
When scanning stalls, switch to counting cells: any row, column, or box with only two or three empty cells is close to forced. List the missing digits and check each empty cell against its column and box — one placement is usually compelled.
On hard puzzles, notes become essential. Pencil in candidates for the tightest regions, then hunt for naked pairs: two cells in a unit sharing the same two candidates eliminate those digits everywhere else in the unit. Its cousin, the hidden single — a candidate appearing in just one cell of a unit — is the most common breakthrough.
Never guess. Every proper sudoku has exactly one solution reachable by logic, and a wrong guess costs you a mistake and, on Expert, the game. If you're truly stuck, re-scan with fresh eyes; the forced move is nearly always something simple you skimmed past.