How to play Lampwise
Lampwise is a daily light-up logic puzzle. You place lamps on a grid of tiles and walls until every tile is lit, without any lamp shining on another. A puzzle takes two to eight minutes.
The rules
- Light every tile. Walls don't need light.
- A lamp lights its row and column in all four directions, until the light hits a wall or the edge of the board.
- Lamps never light each other. Two lamps can share a row only if a wall stands between them.
- A number on a wall tells you exactly how many lamps touch it on its four sides. Corners don't count. A wall without a number can have any number of lamps next to it.
Every puzzle has exactly one answer, and you can always reach it by logic alone.
Controls
- Tap once to place a lamp.
- Tap twice to swap the lamp for a dot, your note that a tile has no lamp. A third tap clears the tile.
- Drag across tiles to dot several at once.
- On a keyboard: arrow keys move, Space cycles a tile, L places a lamp, X places a dot, Backspace clears it.
- Hint highlights the next step you can prove and explains why.
- A lamp that sits in another lamp's light gets a red ring. A number with too many lamps, or too few free tiles left, gets a red ring too.
Six techniques that solve every board
Every Lampwise puzzle can be finished with the moves below. Easy puzzles need only the first three. Medium puzzles add the corner trick or the dark-tile check. Hard puzzles need the last one at least once.
1. Lit tiles stay empty
Once a tile is lit, it can't hold a lamp, because that lamp would sit in another lamp's light. The game shows lit tiles warm, so you can skip them when you look for the next lamp.
2. Full numbers
A 0 means no lamp touches that wall, so dot all four tiles around it. A 4 means a lamp on every side. More generally, compare each number with the free tiles next to it. If the number already has all its lamps, the other neighbors are empty. If it needs exactly as many lamps as it has free neighbors, they all get lamps. A 3 on the edge of the board or a 2 in a corner, with no other walls beside it, is full from the start.
3. The only light
Look at a dark tile and ask where its light could come from: the tile itself, or any free tile in its row or column before a wall. If only one of those tiles is left, the lamp goes there. A tile boxed in by walls has only itself, so it needs a lamp of its own.
4. The corner trick
Take a wall that needs one lamp fewer than it has free neighbors, such as a 3 with four free sides or a 1 with two. It can leave only one neighbor empty, so any two neighbors that meet around a corner include at least one lamp. The tile in that corner, diagonal to the wall, is always lit, so put a dot on it.
5. Would it go dark?
Pick a free tile and imagine a lamp on it. Its light would rule out every free tile in its row and column. If that leaves some other dark tile with nowhere for its light to come from, or leaves a number unable to get its lamps, the tile can't hold a lamp.
6. Follow it through
On hard boards, imagine a lamp on a tile, or imagine the tile empty, and play the simple moves above from there in your head. If you soon reach a tile nothing can light, a broken number, or two lamps in each other's light, the guess was wrong and the opposite is true. Start with tiles beside numbers, where the chain stays short.
Questions
When does a new puzzle come out?
At midnight in your own time zone. The board gets bigger through the week, from 7×7 on Monday to 10×10 at the weekend.
Do I need an account?
No. Your streak, times and progress are saved in this browser. Clearing browser data removes them.
Does using a hint break my streak?
No. Your result just shows how many hints you used.
Is Lampwise the same as Light Up or Akari?
The rules come from a classic pencil puzzle known as Light Up or Akari. Lampwise has its own boards made by our own generator, a new puzzle every day, 300 practice puzzles and step-by-step hints.
Can a puzzle need a guess?
No. Before a puzzle is published, a solver works through it with the six techniques above, step by step. If it ever has to guess, the puzzle is thrown away.