Play 0h n0 Online

About 0h n0

0h n0 is a logic puzzle inspired by the Japanese Kuromasu. Blue numbered dots must see exactly that many other dots in their row and column. Red dots block the view. Choose from four grid sizes (5x5 to 8x8) and build your cumulative score as you solve more puzzles. Simple rules but deeply satisfying logic challenges.

How to Play

1. Each blue number tells how many other dots it can see in its row and column
2. Red dots block line of sight between blue dots
3. Click empty cells to cycle between blue and red dots
4. Fill every cell so all number clues are satisfied
5. Larger grids award more points — build your cumulative score

Controls

• Mouse Click: Place or cycle dot color
• Undo Button: Take back last move
• Help Button: Get a hint for the current puzzle