Nurikabe, known in Japanese folklore as an invisible wall that blocks roads and causes travel delays, is a logic puzzle. It has also been named "Cell Structure" and "Islands in the Stream". The game board is a grid, typically of a rectangular shape, but without a standard size. Some cells on this grid contain numbers.
- The objective is to label each cell as either "black" or "white".
- All black cells must be interconnected.
- Every cell with a number must be part of a white island composed of connected white cells.
- The size of each white island, including the cell with the number, must match the number itself.
- Two separate white islands should not be adjacent to each other.
- Formation of 2x2 black cell blocks is not allowed.
Additional Rules for Nurikabe
- While black cells should be connected, they can't form 2x2 squares.
Basic Solving Tips
- Start by identifying cells that can be immediately labeled as black or white based on the given numbers.
- Ensure no 2x2 black cells are formed.
- Use the grid's edge to help determine which cells must be black to keep white islands separate.
- If an island has reached its required number of white cells, ensure all its adjacent cells are black.
- Look for "choke points" where black cells must be placed to prevent islands from connecting or getting too large.