What is Shikaku?
Shikaku is a quick, visual logic puzzle about areas. The grid is dotted with numbers, and you draw rectangles around them so that each rectangle’s size matches its number exactly. When every cell is covered, you are done.
It is easy to learn and pleasantly tidy to solve. Play Shikaku online free here, from 7×7 warm-ups to big 15×15 grids.
How to play Shikaku
- Divide the whole grid into rectangles or squares.
- Each rectangle must contain exactly one number.
- That number equals the area of the rectangle, counted in cells.
- Every cell belongs to exactly one rectangle.
Shikaku tips
Big numbers and prime numbers first
A 7 can only be a 1×7 line, and a large number near a wall has few shapes that fit. Place those before the flexible ones.
Check which number can reach a cell
When an empty cell can only be covered by one number's rectangle, that rectangle must stretch to include it.
Use the 1s and 2s last
Small numbers fit almost anywhere, so leave them until the big rectangles have claimed their space.
Frequently asked questions
What does Shikaku mean?
Shikaku is Japanese for square. The puzzle is also called Rectangles or Divide by Box.
Can a rectangle be a single cell?
Yes. A cell with the number 1 is a 1×1 square on its own.
Is there always one solution?
Yes. Each puzzle has one valid way to split the grid.
