How to Play
The grid has nine rows, nine columns, and nine 3x3 boxes, with some digits already filled in. Fill in the rest so that every row, every column, and every box contains each digit from 1 to 9 exactly once.
Tap a cell to select it, then tap a number on the pad below the grid. The selected cell's row, column, and box are shaded, and every copy of its digit lights up, so you can see at a glance where a number can still go. Switch on Notes to pencil in small candidate digits instead of an answer. On a keyboard, type the digits and press N for notes.
Rules
- A digit may appear only once in each row, column, and 3x3 box. Digits that break this rule turn red.
- Every puzzle has exactly one solution and can be solved by logic alone, without guessing.
- Today's puzzle is Medium, the same for everyone, and ranked by how long it takes you. Only your first solve of the day counts.
- The clock starts when you press Start and stops whenever the puzzle is off screen: paused, in another tab, or after you leave the page.
- Using a hint on today's puzzle means that solve is not ranked. Practice puzzles are never ranked.
Tips & Strategy
Start with crowded lines
Rows, columns, and boxes with six or seven digits leave few gaps. Check which digits are missing and where each can fit.
Hunt one digit at a time
Tap a 5 to light up every 5, then look for a box with only one spot left for it.
Use notes on harder puzzles
When nothing is obvious, pencil in candidates. Placing a digit clears it from the notes of every cell it sees, so patterns like two cells sharing one pair stand out.
Trust logic over luck
If you catch yourself guessing, step back: every puzzle here can be solved by reasoning.
FAQ
What makes a puzzle Easy, Medium, or Hard?
The solving techniques it needs, not how many digits are given. Easy needs only singles. Medium also needs pointing pairs and naked or hidden pairs. Hard adds triples, X-Wings, and XY-Wings.
Can I leave and come back later?
Yes. Your grid, notes, and time are saved in this browser. The clock stays paused until you press Resume.
How is my time checked?
When you solve today's puzzle, every change you made is sent with its time. The server rebuilds the puzzle, replays your moves, and ranks the time only if the grid ends up solved.
Why can't I improve my time today?
Once solved, you know the answer, so only your first solve counts. A new puzzle arrives at midnight UTC.