🟥 Shikaku
🧩 Logic · 3 playsShikaku
Divide the grid into rectangles, one number in each, matching its area.
About Shikaku
The grid has to be cut up entirely into rectangles, each containing exactly one of the printed numbers, and that number gives the rectangle's area in cells. Nothing may overlap and no cell may be left over. Prime numbers are the way in: a 7 admits only a strip one cell wide and seven long, and the nearest edge usually decides which way it lies. The later stages turn on the cells that no rectangle can reach, which quietly dictate the shape of everything around them.
How to Play
Drag across the grid to draw a rectangle. Each rectangle must hold exactly one number, and its area in cells must equal that number. The rectangles must cover the whole grid with no overlaps. Start with numbers that allow only one shape.
💡 Tips & Strategy
Prime numbers and cells near the edges are the easiest openings. A 5 can only ever be a 1 by 5 or 5 by 1 rectangle, and a clue tight against a wall or corner loses most of its orientations immediately. Place the forced rectangles first and the board shrinks around them.
Treat every other clue as a wall. No rectangle may contain two numbers, so a candidate shape that would swallow a second clue is dead. Sweeping a clue's possible rectangles against its neighbours eliminates far more than checking it in isolation.
When you stall, reverse the question. Instead of asking what shape a clue takes, pick an empty cell and ask which clues could possibly reach it. If only one can, that cell belongs to that clue's rectangle, and the shape is often pinned by that single fact.
The arithmetic gives you a free check at every stage: the clue numbers sum to exactly the number of cells on the board. If your placements leave an unreachable gap, something earlier is wrong, and it is nearly always a rectangle drawn in the only orientation you happened to notice first.