Nurikabe Online Free
Each number is an island of that many squares. Shade everything else as sea, keeping all the sea connected and free of 2 × 2 pools.
Tap to shade sea, tap again for a dot (island), again to clear. Drag to paint.
How do you play Nurikabe?
In Nurikabe you shade squares to make a sea around numbered islands. Each number is the size of its island, every island has exactly one number, all the shaded sea must join up into one connected wall, and the sea can never contain a 2 × 2 block.
It is a Nikoli puzzle named after a wall spirit from Japanese folklore. Start by shading around every 1, then separate squares that sit between two numbers. When you’re comfortable, Heyawake uses a similar rule that the white squares must stay connected.
How to play Nurikabe
- Every number belongs to a white island containing exactly that many squares, including the number itself. Each island has exactly one number.
- Islands can’t touch each other along a side.
- All shaded squares (the sea) must connect into one area, and no 2 × 2 block can be completely shaded.
- Tap a square once to shade it, again to mark it with a dot (a square you know stays white), and a third time to clear it. Drag to fill several squares the same way. Every puzzle is made fresh and checked to have exactly one solution, so it can always be solved by logic without guessing. Use Hint if you’re stuck, and pick a size at the top of the board.
Nurikabe skills
- Counting and area
- Logical deduction
- Keeping a region connected
Level: Ages 9 and up
Tips for Nurikabe
Every 1 is a finished island: shade all its neighbours straight away.
A square between two numbers (in a row, or diagonally) must be sea, or two islands would touch.
Look at 2 × 2 blocks of unknown squares. At least one must be white, so some island has to reach it.
Nurikabe questions and answers
What is Nurikabe?
Nurikabe is a Nikoli puzzle named after a wall spirit from Japanese folklore. You shade squares to form one connected wall, or sea, leaving white islands whose sizes match the numbers.
Why can’t there be a 2 × 2 shaded block?
It’s one of the rules that keeps the puzzle to a single solution. Without it, you could shade almost everything. It also gives you a powerful clue: every 2 × 2 area needs at least one white square.
Which size should I start with?
Start with 5 × 5 to learn the rules, then move up to 7 × 7. The 9 × 9 puzzles have more islands and take longer.