Just Shikaku
Carve the grid into rectangles. Every rectangle holds exactly one number, and that number is its area.
Today's room
One room a day, built around one named technique. The same room as in the app.
A new room
The rules
- Every rectangle holds exactly one number.
- The number is the rectangle's area in cells.
- Rectangles never overlap, and no cell is left over.
Drag to draw a rectangle. Tap one to lift it. Drawing over a rectangle replaces it. With a keyboard: arrow keys, Space to start and to lay, Backspace to lift.
The techniques
The solver that builds each room knows 7 named techniques, listed here in the order it reaches for them. A room is kept only if they are enough to finish it.
- Ones: A 1 is its own mat
- Prime Strips: Primes are strips
- Only Fit: One fit left
- Common Ground: Every fit shares cells
- Lone Reacher: Only one clue reaches
- No Orphans: Don't strand a cell
- Count the Room: The areas don't add up
Questions
Do I ever have to guess in Shikaku?
No. Every room is proved to have exactly one solution before it reaches you, and each step can be reasoned out.
Is Shikaku free to play here?
Yes. Today's room and new 5×5 and 7×7 rooms at every difficulty are free, with no account and no ads. The 10×10 and 12×12 rooms, the lessons, the drills and the hints are in Just Shikaku, the app.
Is today's room the same as in the app?
Yes. The daily room is made from the date, so this site and the app serve the same one.
Along the street
In the app
Seven named techniques, each with its own lesson. Hints that name the technique and draw the argument on your board. 10×10 and 12×12 rooms, timed drills, and a replay that grades every rectangle you laid. One purchase, no ads.