Logic GamesLogic & pattern practice
Minesweeper guide
Read neighboring counts and compare overlapping clues.
Puzzle practice guide
How to play Akari
Solve Light Up puzzles with wall clues and sight lines.
Play Akari, also called Light Up, online and practice turning illumination into deductions. A bulb solves one part of the board while restricting every open cell it can see. Scan both numbered walls and cells that have very few possible light sources.
01 / The essentials
Akari rules
- Place bulbs in open cells so every open cell is illuminated.
- Light travels horizontally and vertically until it meets a wall or the board edge. Two bulbs must not shine directly on each other.
- A numbered wall requires exactly that many bulbs in its orthogonally adjacent cells. Diagonal bulbs do not count toward the clue.
02 / Build the habit
Akari strategy
Finish wall counts
A zero excludes bulbs from all its adjacent open cells. For other clues, compare the remaining required bulbs with the number of still-available neighboring cells. Equal counts force all of those cells.
Follow the light
After placing a bulb, exclude every cell along its unobstructed row and column from holding another bulb. Then revisit nearby wall clues because their remaining candidates may have changed.
Find a sole light source
For an unlit cell, inspect the cell itself and all open cells along its sight lines. If only one can still hold a bulb, place it there even if no numbered wall is nearby.
03 / Worked example
A wall forces its neighbors
A wall marked 2 has only two adjacent open cells; its other sides meet walls or the board edge. Both open cells must contain bulbs. Each new bulb then prevents any second bulb along its clear sight lines.
04 / Put it into practice
A Akari practice plan
- Begin a board by resolving zeros and clues with exactly enough adjacent cells.
- Next, choose the hardest-to-light empty cell and list its possible light sources.
- On a fresh board, alternate wall counting and illumination checks after every placement.
A common mistake
A lit board is not necessarily solved. Every numbered wall must have the right adjacent bulb count, and no pair of bulbs may see each other.
Can light pass through a numbered wall?
No. Both numbered and unnumbered walls stop light. A bulb beside a wall can illuminate along its other unobstructed directions.
Guide updated . Rules describe the version on Logic Games.