Light Up
Bulbs left: 0
- Category
- Puzzle
- Players
- 1
- Controls
- Tap
- Grid
- 7 x 7
- Loads
- Plays instantly
Controls
| Tap a white cell | Place or remove a bulb. |
Next up
| Tap a white cell | Place or remove a bulb. |
Light Up, known in Japan as Akari, gives you a grid with black walls scattered through it. Place bulbs so that every white cell is lit, where a bulb shines along its row and column until a wall stops it. The catch is that no bulb may shine on another.
Numbered walls are what make it a deduction puzzle rather than a covering exercise. A wall marked four must have a bulb on all four sides, which fixes those cells immediately and rules out everything they illuminate.
Start with the numbered walls. A wall marked with the number of free neighbours it has forces bulbs onto all of them, and a wall marked zero forbids bulbs on every side.
Look for cells no bulb can reach. A white cell tucked behind walls can only be lit from one direction, which forces a bulb into a specific place.
Watch for bulbs facing each other. Two bulbs in the same row with no wall between them is always wrong, and it is the mistake that undoes most attempts.
Work outward from corners. Corner cells have the fewest lines of sight, so they are constrained early and give you a foothold into the middle.
Along its row and column until a wall blocks it.
No, that is the central restriction of the puzzle.
How many bulbs must sit directly beside that wall.
Yes, each is built by placing valid bulbs first and reading the wall numbers off them.
No sign-up, no email, no account. Open the page and Light Up is ready to play straight away, on a phone or a desktop.