Mouse
- Click a cell to select
- Use on-screen digits or keyboard to enter
- Toggle notes to add candidates
Overview 
Sudoku
스도쿠
Fill the grid so every row, column, and 3×3 box contains 1–9 exactly once.
Language-free, logic-first, and endlessly replayable—from quick warmups to brain-melting grids.
Logic PuzzleNumber Puzzle
Goal & Core Rules
Complete a 9×9 grid with digits 1–9 so that each row, column, and 3×3 box has no repeats.
- Each row must contain 1–9 exactly once.
- Each column must contain 1–9 exactly once.
- Each 3×3 box must contain 1–9 exactly once.
- Well-posed puzzles typically have a single unique solution.
Controls
Keyboard
- 1–9 to enter
- Backspace/Delete to clear
- N toggles notes (if supported)
- Arrow keys to move (if supported)
Touch
- Tap to select
- Use a number pad to enter
- Long-press/button to toggle notes (if supported)
Beginner Tips
- Start with singles: cells that have only one possible digit.
- Scan rows/columns/boxes for missing digits to spot easy placements.
- Use notes sparingly—write candidates where they meaningfully narrow choices.
Advanced Tips
- Hidden singles and pairs solve a large portion of puzzles without guessing.
- When stuck, revisit the most constrained unit (row/col/box) to eliminate candidates.
- Track which techniques you used by difficulty to improve faster.
Origins & History
The modern form appeared in 1979 in the U.S. as “Number Place,” was introduced in Japan by Nikoli in 1984 (which shortened the name to “Sudoku”), and then spread globally through newspapers in the mid-2000s.
Timeline
- 1979 Published by Dell as “Number Place.”
- 1984 Nikoli introduced it to Japanese readers; the long Japanese title was shortened to “Sudoku.”
- 2004 Widely syndicated in newspapers outside Japan, igniting a global boom.
Notable People
- Howard Garns Credited with creating “Number Place” (published in 1979)
- Nikoli Introduced it in Japan and popularized the name “Sudoku”
- Wayne Gould Helped popularize Sudoku in newspapers outside Japan in 2004
FAQ
Is Sudoku luck-based?
Proper Sudoku is designed to be solvable by logic, typically with a unique solution.
Do I need pencil marks?
Not required, but very helpful on intermediate and advanced puzzles.
Is guessing allowed?
You can, but focusing on logic techniques usually builds skill faster.