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Divide the grid into non-overlapping rectangles. Each rectangle must contain exactly one number, and that number equals the rectangle's area.
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About Shikaku
Shikaku (also known as Rectangles) is a Japanese logic puzzle where you divide a grid into non-overlapping rectangles. Each rectangle must contain exactly one number, and that number tells you the rectangle’s area. Your job is to determine the dimensions and position of every rectangle so they tile the entire grid perfectly.
The logic is driven by factorization: a cell containing “6” could be covered by a 1×6, 6×1, 2×3, or 3×2 rectangle. Grid boundaries and neighboring rectangles then eliminate most options, leaving you with the unique valid placement. Shikaku puzzles always have exactly one solution.
What makes Shikaku particularly enjoyable is that it requires almost no arithmetic — you just need to think about shapes and spaces. It’s an excellent puzzle for visual thinkers and a great entry point for people new to Japanese logic puzzles.
Numbers near corners and edges are the best starting points, since the grid boundary immediately eliminates many rectangle orientations. Work inward from these anchors to fill the grid systematically.
Frequently asked questions
What is Shikaku?
Shikaku is a logic puzzle where you divide a grid into rectangles. Every cell must be in exactly one rectangle, each rectangle contains exactly one number, and that number equals the area (number of cells) of the rectangle.