Play Kurodoko Online — Free
Shade cells so numbered cells can "see" exactly that many white cells in their row and column. Shaded cells cannot touch, and all white cells stay connected.
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About Kurodoko
Kurodoko (Japanese for “Where is Black?”) is a puzzle where you place black cells in a grid, some of which contain numbers. Each numbered white cell can “see” other white cells in all four directions until blocked by a black cell — and the number tells you exactly how many white cells it can see, including itself. Black cells cannot be adjacent, and all white cells must remain connected.
The visibility mechanic makes Kurodoko feel like a cross between Hitori and Light Up. A numbered cell with a large value must have long clear sightlines, forcing many nearby cells to stay white; a small value forces black cells to cut its sightlines short.
Kurodoko is less widely known outside Japan but has a devoted following among fans of visibility-based logic puzzles. The simultaneous constraints — visibility counts, no adjacent black cells, white connectivity — create deeply satisfying logical challenges where a single placement ripples across the grid.
A clue of 1 is the most powerful: the cell sees only itself, so all four orthogonal neighbors must be black. Start with 1-clue cells to establish the first black cells, then use the no-adjacency rule to mark their neighbors as definitively white.
Frequently asked questions
What is Kurodoko?
Kurodoko means "Where is Black?" Numbers in white cells tell you how many white cells that cell can see horizontally and vertically (including itself), up to the next black cell. Black cells cannot touch each other, and all white cells must be connected.