Partition the whole grid into rectangles, each containing exactly one numbered clue equal to its area.
A clue of 6 can be 1×6, 2×3 or 3×2 — list the possible rectangles, then let neighboring clues eliminate options.
Prime-numbered clues (5, 7, 11…) have only one possible shape and are the best places to start.
Yes — it plays directly in your browser with no download or registration.
Each number is the exact area of the rectangle that contains it, and every rectangle holds exactly one clue.
No — any rectangle works as long as its area matches its clue and it contains no other clue.
Yes, each size and difficulty gets a fresh official board every day, all archived.
Shikaku (literally 'divide by squares') comes from the great Japanese puzzle tradition, and this version keeps everything that made it a classic while making it effortless to play daily. Each puzzle is a rectangular grid with number clues; you draw rectangles that must contain exactly one clue each, and that clue must equal the rectangle's cell count. The deductions start arithmetic — a prime clue like 7 can only be 1×7 — and end geometric, as the remaining free space forces the shape of the last rectangles. Because every rectangle you place shrinks the free area, mid-game boards turn into a friendly negotiation between the factors you know and the spaces that remain. Four daily sizes serve everyone from beginners to experts, the drag-to-draw interface feels natural with mouse or finger, and validation is instant so wrong rectangles never sneak through. The daily archive keeps every past board playable, and hints reveal a single rectangle at a time — enough to unstick, never enough to spoil.