Puzzle guide
How to solve Akari
In Akari you light up a dark room. Each lamp shines along its row and column until a wall stops it, and no two lamps may shine on each other. The numbers on the walls tell you how many lamps stand right next to them. Here is how to place every lamp.
The rules
- Place lamps in the open cells until every one of them is lit.
- A lamp lights its own cell and every cell in the four directions until a wall blocks it.
- No lamp may light another lamp.
- A wall with a number has exactly that many lamps right next to it (above, below, left and right). A wall without a number says nothing.
A solved puzzle
Your first moves
- Find every 0 and put a dot on its neighbours: no lamp goes there.
- Find walls whose number equals their free neighbours, like a 2 in a corner. All of those neighbours are lamps.
- After every lamp, put dots along its light: no other lamp can stand there.
- Look for dark cells that only one free cell can still light. That cell gets a lamp.
Techniques, step by step
A 0 wants no lamps
A wall with a 0 has no lamps next to it. Put a dot on each of its neighbours. A dot means: no lamp here. Those dots often leave other cells with only one way to be lit.
A wall that needs every neighbour
A 2 in the corner has only two free neighbours, and it needs two lamps. So both neighbours are lamps. The same works anywhere a number equals the free cells around it: a 3 against an edge, a 4 in the middle.
Lamps never see each other
A lamp shines along its row and its column until it hits a wall. Every cell in that light can never hold another lamp, because the two would light each other. Put a dot on all of them. Do this right after you place a lamp, and the next steps get much easier to see.
A full wall
This 1 already has its lamp next to it. It needs no more, so every other neighbour gets a dot. Whenever a numbered wall has all its lamps, close off the rest of its sides.
The only lamp for a dark cell
The top-left cell is still dark, and it has a dot, so it cannot light itself. The cell to its right has a dot too. The only cell left that can shine on it is the one below. So that cell is a lamp. Hunting for dark cells with just one possible light is what solves most easy and medium boards.
Diagonal to a 3
A 3 in the middle needs lamps on three of its four sides. A lamp on a cell diagonal to it would light two of those sides at once, so neither of them could hold a lamp, and the 3 would have only two sides left. So the four diagonal cells of a 3 get a dot. The same kind of look-ahead works for 2s and 1s: before you place a lamp, ask what it takes away from the walls around it.
Common mistakes
- Two lamps in one line of light. Walls stop the light, nothing else does. Two lamps in the same row with no wall between them see each other.
- Counting diagonal lamps for a wall. A number counts only the four cells directly above, below, left and right of it.
- Forgetting the dark cells. The puzzle is finished only when every open cell is lit. The app does not mark a cell that stays dark, so check the corners and short corridors.
- Not using dots. Dots show you where lamps can no longer go, and they are what leaves a cell with only one light.
Questions and answers
Ready to play?
Dots around the 0s, lamps where a wall needs them, dots along every light, and the one lamp that can reach a dark cell: that is how Akari's rooms light up.