Shikaku one clue, one exact rectangle
Drag a rectangle or tap two opposite corners. Every clue must own exactly its area. Progress saves automatically; proof tools stay out of the way until you ask.
Drag corner to corner or tap two corners · tap a placed patch to remove it
Draw a rectangle around one clue so its area equals the clue.
Autosaves on this device · practice seeds and Daily dates have permanent replay links
Tools & options
Shows how many legal rectangles remain for each open clue from the rectangles you have committed. Opening this marks the run Assisted.
Enter start/place · arrows move · Esc cancel · Delete erase · H hint · R restart · ⌘/Ctrl Z undo
Progress & recent solves
No completed Shikaku yet.
How to play & solving strategy
One clue per rectangle. Its area must equal the clue, rectangles cannot overlap, and every cell must be covered.
Start with constrained clues. Prime areas often have only a few shapes, edge clues lose many placements, and cells reachable by only one clue can force an entire rectangle.
Hints explain a deduction. The default Hint first uses only-rectangle and cell-ownership logic, then checks full partition constraints if needed. It never reads the stored reference rectangle as a fallback.