TINY'S PLAYROOM
Sudoku.
Give every row, column, and box its own complete set of numbers from 1 to 9.
Keyboard: arrows select, 1–9 enter, 0 / Delete erase, N toggles notes, Ctrl / ⌘ + Z undoes; add Shift to redo.
Progress and notes save automatically. Refreshing or leaving the window pauses play. Undo history stays in this page only (last 100 moves).
Choose a space and make your first move. Spaces filled: 0/81. Conflicting cells: 0.
About this game
About the Sudoku logic puzzle
Sudoku is a placement puzzle rather than an arithmetic exercise. A 9 × 9 board contains nine 3 × 3 boxes. Fill its spaces with 1 through 9 so that each row, column and box has no repeated number. Fixed clues start the reasoning, and each confirmed entry helps eliminate candidates elsewhere.
Every generated puzzle is checked for a unique solution. The three levels target 42, 34 and 28 clues; the actual count appears on the board and the reasoning required varies. Organize possibilities with pencil notes, check your entries or request a single-cell hint when you need help.
Features in this version
Clues and pencil notes
White numbers are fixed clues and blue numbers are your entries. Notes hold multiple candidates. Entering a number removes that candidate from its row, column and box; undo restores affected notes.
Conflicts and checks
Repeated numbers turn red automatically. A nonconflicting entry is not necessarily correct: Check compares your entries with the answer, while Hint fills one correct number.
Saved puzzles and records
The puzzle, entries and notes save locally and restore paused. Undo and redo cover the last 100 moves in this page only. Games using hints do not count toward best times without hints.
Getting started
- Look for a cell with just one possible number by ruling out values already present in its row, column and box.
- Review each group from the number's perspective. If a digit can occupy only one position in a row, column or box, that position is determined.
- Write notes when several possibilities remain instead of guessing immediately. After every confirmed entry, review the groups it affects.
Frequently asked questions
Are entries correct if no conflicts are red?
Not necessarily. Automatic conflict marking detects repeats, but a wrong entry can remain nonconflicting. Check compares entries with the unique answer; a complete board must satisfy every rule.
Can I undo a hint to keep a best time without hints?
No. Hint counts remain after undo so assisted puzzles cannot become records without hints. You can still continue and complete the puzzle.
Do notes and undo history survive a refresh?
The puzzle, entries and pencil notes save in this browser and restore paused. Undo and redo history belong to the current page and are not retained on refresh.