Follow one digit and a single cell lights up. Fill it, and the next one appears.
Made by the same generator as the app: one answer, reachable by logic alone. Hints come in three steps.
What makes it fun
"The 7 can only go here"
Track one digit and the answer cell stands out.
One cell calls the next
The more you fill, the faster it goes.
The key is in your notes
On hard grids, your own notes break it open.
Rules
- Fill the empty cells with 1–9.
- Each row, each column and each 3×3 box with thick borders holds 1–9 exactly once.
- The dark digits are given at the start and cannot be changed.
SOLVED WHENSolved when every empty cell holds the right digit.
Your first move
Look for the row, column or box with the most digits. If only one or two are missing, their places are easy to narrow down.
When you get stuck
Hints come in three steps: where to look, why it works, then the answer. The first step only shows the place, so you can still find the rest yourself.
Controls
- Long-press to enter
- Long-press a cell, slide to a digit and let go. Let go outside the keypad to enter nothing.
- Cell, then number key
- Tap a cell, then press a number key. You can check which cell is selected before you press.
- Digit first
- To place the same digit in many cells, pick its key once, then tap each cell.
- Notes
- Double-tap a cell or switch on Notes to write small candidates. Notes never count as mistakes.
- Erase, Undo, Redo
- Erase clears the selected cell. Undo steps back one move, and Redo brings it back.
Records and practice live in the app
The web version is for playing only and keeps no records. The app adds:
- Ranked matches and tiers that follow your level
- Technique training, one technique at a time, plus the basic rules
- Your solve history, achievements and progress over time
Some techniques you can train
- Hidden single
- Naked single
- Pointing
- Naked pair
- X-Wing
- XY-Wing
STORENot on the App Store or Google Play yet. Store links will appear on this page once they are live.
