Light Up
Place bulbs until every white cell is lit.
About Light Up
Light Up — known in Japan as Akari — is a classic logic puzzle about placing lamps in a dark room. Numbered walls tell you how many lamps touch them, and every puzzle has exactly one solution you can reach by pure logic.
How to play
Put bulbs on white cells. A bulb lights its whole row and column until a black cell blocks it. Every white cell must be lit, no bulb may shine on another bulb, and a numbered black cell has exactly that many bulbs directly next to it.
Tips and strategies
- A black 4 has bulbs on all four sides; a 0 has none — mark those cells.
- A white cell that only one spot can light must get a bulb there.
- Mark cells that can't hold a bulb with a dot to keep track.
Light Up strategy guide
Start with the 4s and 0s. A 4 has bulbs on all four sides; a 0 has none, so mark its neighbours with dots. A 3 against the edge or another black cell is just as full.
Look for white cells that can be lit only one way. If no bulb could reach a cell except one placed on it — or on one other cell — that is where the bulb goes.
Dot every cell that can't hold a bulb: cells next to a satisfied number and cells already lit by a bulb. The fewer open cells remain, the easier the last bulbs are to see.
Frequently asked questions
How do I play Light Up?
Put bulbs on white cells so every white cell is lit. A bulb lights its row and column until a black cell, no bulb may shine on another bulb, and a numbered black cell has exactly that many bulbs directly next to it.
Is Light Up the same as Akari?
Yes — Akari is its Japanese name. You can play 7×7, 10×10 and 12×12 boards.
Does every Light Up have a unique solution?
Yes. Numbers are hidden from black cells only while the solution stays unique, so the numbers you see are the ones you need.
Is Light Up free to play?
Yes. Every game on Puzzimo is completely free and runs in your browser on desktop, tablet and phone — no download or installation.
Do I need an account?
No. You can play instantly as a guest and still appear on the leaderboards. Sign in with Google, Discord or LINE to keep your scores on every device.
How does the daily Light Up challenge work?
Every day at 00:00 UTC everyone gets the same new puzzle. Only your first finish of the day counts on the leaderboard.
How are leaderboard results verified?
Our servers replay every move of your game and measure the time themselves, so leaderboard results can't be faked.