Shikaku
Shikaku is a logic puzzle about cutting a grid into rectangles. Each rectangle must hold exactly one number, and that number is its area, the count of cells it covers. Every cell belongs to exactly one rectangle.
How to play
Every Shikaku here has exactly one solution and can be solved by logic alone. The grid grows from 6×6 at Easy to 10×10 at Expert, and the level is set by the hardest technique the puzzle needs.
- Split the whole grid into rectangles (squares count).
- Each rectangle holds exactly one number.
- That number equals the rectangle's area.
Playing on this site
- Drag from one corner to the opposite corner to draw a rectangle; its area shows as you drag.
- Drawing over other rectangles replaces them, and a tap on a rectangle erases it.
- A rectangle that fits its number is tinted; one that cannot is outlined red with a cross.
- Hint points out wrong rectangles first, then names the next technique and shows the rectangle it settles.
- Your puzzle is saved in this browser, so you can come back to it later.
Techniques by level
Every technique the solver knows, from easiest to hardest. A puzzle's level is the hardest one it needs.
Easy
- Only one shape
- This number fits only one rectangle that keeps clear of other numbers and drawn rectangles.
- Only one number reaches
- A cell only this number's rectangles can cover belongs to it, which leaves it one shape.
Medium
- Shared cells
- Every rectangle of some number covers the same cells; no other number may use them.
Hard
- Leave room
- The other shapes would leave a number or a cell with no rectangle at all.
Expert
- Contradiction
- The other shapes run into a dead end a few steps later.
Questions
Where should I start a Shikaku?
Large numbers near corners and edges often fit only one way, and so do primes like 7 or 11 squeezed between other numbers. Draw those first.
Will I ever have to guess?
No. Every puzzle has exactly one solution that logic alone reaches, at every level.
Is Shikaku free to play here?
Yes. Every level is free, with no account and no sign-in.