CLASSICTactician’s Table10–30 min
Chess
Standard chess with White and Black taking turns under ordinary movement, capture, castling, en passant, and promotion rules.
Sudoku
Fill a nine-by-nine grid so every row, column, and three-by-three box contains the digits 1 through 9 once.
Solo or a room · 1–4 players
Sudoku
Fill every empty square so each row, column, and 3×3 box contains 1–9 once.
No sign-up · Rooms stay on this device / tabs · Saves on this deviceAbout this game
About Sudoku
Fill a nine-by-nine grid so every row, column, and three-by-three box contains the digits 1 through 9 once. Each Questly puzzle is a transformed, seeded layout with notes, keyboard entry, and mistake tracking. Solo play is one puzzle. In a room of up to four, everyone receives the same grid and races to a valid solution.
How to play
How to play Sudoku
Fill every empty square so each row, column, and 3×3 box contains 1–9 once.
Select an empty cell and enter a digit. Notes mode stores candidates without committing an answer. In a room, the first finished valid grid wins.
01
Find an empty square
Choose an empty square and check its row, column, and 3×3 box.
02
Rule out used numbers
For hard squares, turn on Notes and record every possible candidate; notes never count as answers.
03
Place the answer
Turn Notes off and enter the final number. Confirmed answers automatically clean matching candidates from nearby squares.
Tips for Sudoku
- When a box has only one place left for a digit, place it before guessing.
- Pencil marks help, but they are not answers.
- A mistake costs points and is not written onto the board.
Controls & accessibility
Controls: Tap a square and number, or use arrow keys and 1–9. Toggle Notes—or hold Shift—to enter candidates without committing an answer. Play in a current mobile or desktop browser; no installation or account is required.
Frequently asked about Sudoku
How many players can join?
One to four. Solo is a single puzzle. A room races the same seeded grid.
Are guesses allowed?
You can try a digit. An incorrect answer is rejected and counted as a mistake.
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