Akari

• Placement
• Regions

Light every white cell by placing bulbs so that no bulb shines on another.

1. Place bulbs in white cells. Each bulb shines horizontally and vertically until a black cell or the edge stops the light.
2. Every white cell must be illuminated and two bulbs may never see each other.
3. A number in a black cell gives the exact number of bulbs in its orthogonally adjacent cells.

• Start with walls marked 0 or with exactly as many available neighbours as required bulbs; then inspect sightlines.
• A 0 clue immediately rules out bulbs in all four adjacent cells.
• If a white cell can receive light from only one position, that position must contain a bulb.
• Mark cells that cannot contain a bulb with × so you do not lose deductions.

Akari, also called Light Up, belongs to the family of logic puzzles published by the Japanese publisher Nikoli.

• A 0 clue immediately rules out bulbs in all four adjacent cells.
• If a white cell can receive light from only one position, that position must contain a bulb.
• Mark cells that cannot contain a bulb with × so you do not lose deductions.

• Where should I begin? Start with walls marked 0 or with exactly as many available neighbours as required bulbs; then inspect sightlines.
• What makes this game different? A number in a black cell gives the exact number of bulbs in its orthogonally adjacent cells.