Light up every cell
Place bulbs on the grid so that light reaches every white cell — but no two bulbs may shine on each other, and the numbered walls demand an exact count of neighboring bulbs. Pure deduction, one unique solution per board. Free, instant, unlimited — no registration.
What is Akari?
Akari — also known as Light Up — is a classic Japanese grid-logic puzzle. The board mixes white cells and dark walls; some walls carry a number. You place light bulbs on white cells, and each bulb beams light along its row and column until a wall blocks it. The goal: every white cell lit, no bulb ever shining on another bulb, and every numbered wall touching exactly that many bulbs.
Every board here is generated so it can be cracked with pure logic — one unique solution, no guessing, the same no-guess promise as every Funduk Games puzzle. Play unlimited boards in 7×7 or 10×10, or take the shared Daily Challenge and build a streak.
The rules
- Tap a cell to place a 💡 bulb (tap again for a · dot, again to clear).
- A bulb lights its entire row and column until blocked by a wall.
- No bulb may shine on another bulb.
- A numbered wall touches exactly that many bulbs (up, down, left, right).
- Win when every white cell is lit.
Frequently asked questions
- Is Akari free?
- Yes — completely free, supported by ads. No download, no login.
- Do I ever need to guess?
- No — every board is verified solvable by step-by-step deduction with exactly one solution.
- What do the dots do?
- Dots are your own notes marking "no bulb here" — proven-empty cells. They make chains of deduction much easier to see.
- Is there a daily puzzle?
- Yes — a shared 10×10 Daily Challenge with streaks, plus unlimited random boards.
Quick solving tips
- Start with 0s and 4s. A 0 forbids bulbs on all its neighbors — dot them. A 4 demands bulbs on all four.
- Corners and walls squeeze 3s. A 3 on the edge or a numbered wall whose free neighbors equal its count is forced immediately.
- Watch the lonely cells. A cell that no other candidate can reach must hold a bulb itself.
- Dots are deductions. Every cell a bulb sees is dot-able; every satisfied number dots its remaining neighbors. The board solves itself dot by dot.
See worked examples in the Akari strategy guide.
More logic puzzles
If you enjoy Akari, try our other no-guess logic games: Nonogram (picture cross), Minesweeper (no-guess boards), Pipes (rotate & connect) and CrownGrid.