A free Akari-style logic puzzle in your browser. Set bulbs so they light the whole grid, never shine on each other, and satisfy every numbered wall. New boards forever, no sign-up.
Tap a cell to place a bulb, tap again for an ✕, tap once more to clear.
New puzzles are built in the page: black walls are scattered first, a valid bulb layout is solved for, and the walls are numbered from that layout — so every board has at least one solution. Start on 7×7 to learn the feel, then step up to 9×9 and 10×10. Enjoy slow deduction? The Hashi Bridges and Slitherlink pages scratch the same itch.
Light Up — also known as Akari — is a bulb-placing logic puzzle. Light every white cell, keep bulbs from seeing each other, and satisfy the numbered walls. No timer, no account.
Tap a white cell once to place a bulb, tap again to mark it with an ✕ where a bulb cannot go, and tap a third time to clear it. Conflicts show live: red bulbs see each other, red numbers are unmet.
Each number counts the bulbs that must sit in the four cells directly around that wall. Plain black walls carry no constraint.
Only with a wall between them. Along any unbroken run of white cells — horizontal or vertical — at most one bulb is allowed.
Yes. Boards are generated around a hidden valid bulb placement and numbered from it, so at least one solution always exists.
Yes. Everything is one tap away. The board scales to your screen and nothing needs installing.