Our playing guide
0h n0 · How to play
0h n0 describes four straight sight lines rather than eight neighboring squares. Red dots stop a line, while blue dots extend it.
Controls
Tap to cycle red and blue. Red blocks sight; a clue does not count itself.
Rules & goal
- A number counts visible blue dots above, below, left and right, excluding itself.
- Red dots and the board edge block sight. Every blue dot must see at least one other blue dot.
- Color all empty cells so every numbered sight line and blue-dot rule is satisfied.
Beginner tips
- If a clue already sees enough blue dots, close its unused directions with red.
- Large numbers need longer blue corridors. Compare routes shared by several clues.
Progress & devices
Play in a desktop or mobile browser using the controls above. Some games save only in the current browser; clearing site data can remove saves. Pause when stepping away. Reloading is not guaranteed to preserve the current round.