Island of 1
"Island of 1" is a puzzle-solving technique that revolves around a unique island consisting of a single square. The objective is to strategically surround this island by shading the horizontally and vertically adjacent squares, effectively creating a protective wall.
Therefore, if we see that there is a Block of 1, we can immediately shade the surrounding squares.
You can see how it looks in the examples below.
.png&w=3840&q=75 "Island of 1")
.png&w=3840&q=75 "Island of 1")
Therefore the "Island of 1" is a very powerful tool in solving Nurikabe puzzles. It is a very common technique and is often the first step in solving a puzzle.