This puzzle is named for a spirit in Japanese folklore that appears as a wall to block travelers. While English names suggest that the regions are seen as islands, the Japanese name suggests that the regions are walls, and the black area is the footpath.
The puzzle appears to have been invented by Nikoli, attributed to the creator Reenin.
Puzzle and Goal
An unsolved puzzle consists of a rectangular (typically square) grid. Some of the cells contain numbers.
The goal is to color in some of the cells to satisfy the clues.
The solved grid must satisfy the following conditions:
The numbered clues indicate the number of cells in the region containing the cell.
Each region contains exactly one numbered clue.
All black cells are orthogonally contiguous.
As "Mochikoro", some regions don't have corresponding number clues.
Cell Structure; Islands in the Stream; Mochikoro; Stream Island; Streaming Content