🔆 Light Up
🧩 Puzzle · 7 playsLight Up
Place the bulbs, light every cell. No bulb may shine on another.
About Light Up
The Japanese logic puzzle also known as Akari, and one of the most satisfying “click, it all fits” solves around. Drop bulbs into the white cells; each one lights its whole row and column until a wall gets in the way. Every white cell has to end up lit, no two bulbs may shine on each other, and a numbered wall needs exactly that many bulbs touching its sides. Clashing bulbs glow red and satisfied numbers grey out, so you always know where you stand. Three sizes — Easy 7×7, Medium 10×10 and Hard 12×12 — each with one unique solution, a timer, undo, and hints that cost you 20 seconds.
How to Play
Tap a white cell for a bulb, again for a ✕ note, once more to clear. Bulbs light their row and column until a wall stops them. No two bulbs may light each other — clashes turn red. A numbered wall touches exactly that many bulbs (up, down, left, right). Light every white cell to solve. Hints add 20 seconds; faster solves score more.
💡 Tips & Strategy
Start with the walls that give everything away. A 4 needs bulbs on all four sides, a 3 against the edge or another wall is just as forced, and a 0 means none of its neighbours can hold a bulb — mark them with ✕ straight away. Crosses are your secret weapon: every cell you rule out makes the rest more forced.
Next, look for white cells only one spot could ever light. If a cell is boxed in by walls and crosses and nothing else in its row or column can take a bulb, the bulb must go on that cell itself. Every bulb you place lights a whole cross of cells, and none of those can hold another bulb.
When a number has exactly as many open neighbours as bulbs it still needs, fill them all; when it's already satisfied, cross off the rest. Each puzzle has one unique solution, so you never need to guess. Hints add 20 seconds and trim your score, so give the numbers one more look before you reach for one.