How to Play Light Up
Place light bulbs in white cells so that every white cell is illuminated. Black cells with numbers tell you exactly how many bulbs are adjacent to them.
Try it now — Easy 7x7 →The Rules
- Place light bulbs in white cells to illuminate every white cell
- A bulb illuminates all cells in its row and column until blocked by a black cell
- No two bulbs may illuminate each other (line of sight)
- Black cells with a number must have exactly that many adjacent bulbs
Available in 4 sizes (5x5, 7x7, 10x10, 14x14) and 3 difficulty levels (easy, normal, hard).
See It in Action
Place light bulbs to illuminate every white cell — bulbs cannot shine at each other
How to Play
- Black cells numbered "0" have no adjacent bulbs — mark all four neighbours as bulb-free
- A black "4" must have a bulb in all four adjacent white cells — place them immediately
- Place forced bulbs, then mark every cell they illuminate to track remaining unlit areas
- Fill remaining unlit cells with bulbs, ensuring no two new bulbs share a line of sight
Pro Tips
A black "1" with only one adjacent white cell forces a bulb there — look for these first
After placing a bulb, immediately mark its entire row and column as "lit" to prevent accidental conflicts
Isolated white cells (surrounded by black cells on three sides) almost always need a bulb
Frequently Asked Questions
What is Light Up?
Light Up (Akari) is a logic puzzle where you place light bulbs in white cells. Bulbs illuminate all cells in their row and column until blocked by a black cell. Every white cell must be lit, and no two bulbs may illuminate each other.
Choose Your Challenge
Start with easy to learn the rules, then progress to harder difficulties.