Visual primer for first-time solvers
Light Up (Akari),
shown not told.
Live demonstrationStep 01 / 07
Step01—Meet the board
This is Light Up (Akari).
A grid of open cells and black walls. One wall carries the number 2 — it's the main clue. Place light bulbs in open cells to illuminate the entire grid. Bulbs shine along their row and column in both directions, stopped only by walls.
Rules in play
- Every open cell must be illuminated by at least one bulb
- No two bulbs may share an unbroken row or column segment
- Numbered walls must have exactly that many adjacent bulbs
Light bulb
Placed in an open cell. Shines along its row and column in both directions until a wall or edge stops it.
Lit vs dark cells
Amber cells are illuminated by a bulb. Grey cells are still dark — every grey cell must eventually be lit.
Numbered wall
White number = constraint active. Green number = exactly that many adjacent bulbs placed — satisfied.