Rules and execise of Nurikabe

Nurikabe has more rules than other puzzles, but popular from beginners to experts.

Rules of Nurikabe

  1. Fill in the cells under following rules.
  2. You cannot fill in cells containing numbers.
  3. A number tells the number of continuous white cells. Each area of white cells contains only one number in it and they are separated by black cells.
  4. The black cells are linked to be a continuous wall.
  5. Black cells cannot be linked to be 2x2 square or larger.




Nurikabe exercise


Let's solve this problem together.


First fill in the cells at the four sides of the 1s (right, top, left and bottom).


Since there cannot be white cells without numbers, you can make the blinking cell black.


Now, look at the cell with the A. This cell should not be black because black cells cannot be linked in 2x2 square or larger blocks. Let's mark it with a dot.

The dotted cell will be a part of a number cell (white) and there is only one number cell that will connect it. So we can also mark the cell under the A cell with a dot.


Now, we know where the left 3 island (connected white cells with only one number - here 3) is. Please paint the cells around the 3 island black so it will not connect to other islands.


Places with "two adjacent numbers (diagonally)" and "the cell between two number cells" are easy hints. These cells will be black, so as not to connect two islands of white cells.


The blinking cell must be black not to isolate the black cell between the white cells of the 4 and the 6.


There are some cells that have to be black so they will separate the white islands.


Now look at the bottom right corner, think like in the previous frame and you will know which cells have to be black and which white.


Making sure all black cells are connected also gives hints.


There are many other clues to solve this kind of puzzle. Find you own ways as you get cleverer at Nurikabe.