How do you play Shikaku?

Divide the grid into rectangles so each one contains exactly one number equal to its area in cells, with every cell covered once. Here you drag across cells to draw each rectangle, and the puzzle clears automatically when the board is fully and correctly covered.

Does every puzzle have only one solution?

Not always. Boards are generated by randomly splitting the grid, so some allow more than one split; any arrangement that satisfies the rules clears the puzzle.

There is no hint button. A rectangle that doesn't contain exactly one number matching its area is outlined in red right away, but a rule-abiding rectangle can still be in the wrong place, so the reasoning is up to you.

What board sizes and records are there?

Three levels: Easy 5×5, Normal 7×7 and Hard 10×10. The clock starts when you press Start and stops at the solve; your best time per level is kept in your browser, and clear times are ranked separately for each level.

Mini Games

Shikaku

Number = rectangle area. Divide the grid with no gaps, no overlaps — a Japanese logic puzzle.

How to Play

Choose a difficulty and press Start. Drag from one cell to another to draw a rectangle.
Each rectangle must contain exactly one number that equals its area. Invalid rectangles get a red border — tap them to remove and redraw.
Overlapping rectangles are rejected. Cover every cell with valid rectangles to clear the board!

Difficulty

My Best Times

Easy 5×5

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Normal 7×7

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Hard 10×10

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Ranking

Rank	Nickname	Score	Detail	Date

Rank	Nickname	Score	Detail	Date
-	You	-	-	-

Your record is only saved in this browser.
Records are not shared across different browsers or devices.

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Shikaku (四角に切れ) is a logic puzzle from Japan: split the grid into rectangles so that each one holds exactly one number and that number equals its area in cells. Every cell has to end up inside exactly one rectangle — no gaps, no overlaps. Drag across cells with a finger or mouse to draw a rectangle. A rectangle that breaks the rule gets a red outline, one that overlaps another is refused, and tapping any rectangle removes it. Undo and Clear All sit under the board, and on a keyboard Backspace, Delete or Z undo your last move. The puzzle clears itself the moment the whole board is covered correctly.

On this board the clues run from 2 to 9 — there are no 1s. Start with the primes 2, 3, 5 and 7: they can only be straight strips, so all you have to decide is the direction. Then use the board edge: a strip can never be longer than the grid, so on 5×5 and 7×7 boards an 8 must be 2×4 and a 9 must be 3×3, and on 5×5 a 6 can only be 2×3. Clues tucked into a corner or against a wall have few ways to grow. When two clues sit side by side, settle the border between them first — it often unlocks the cells around them.

Shikaku is one of the pencil puzzles of Nikoli, the Japanese publisher that gave sudoku its name and created slitherlink. Here every board is generated at random, so a puzzle can occasionally have more than one valid split, and any split that follows the rules counts. Pick Easy (5×5), Normal (7×7) or Hard (10×10): the timer runs from Start to the solve, your best time per level is saved in your browser, and clear times go on a separate ranking for each level.

Frequently Asked Questions

Q. How do you play Shikaku?
A. Divide the grid into rectangles so each one contains exactly one number equal to its area in cells, with every cell covered once. Here you drag across cells to draw each rectangle, and the puzzle clears automatically when the board is fully and correctly covered.
Q. Does every puzzle have only one solution?
A. Not always. Boards are generated by randomly splitting the grid, so some allow more than one split; any arrangement that satisfies the rules clears the puzzle.
Q. Are there hints?
A. There is no hint button. A rectangle that doesn't contain exactly one number matching its area is outlined in red right away, but a rule-abiding rectangle can still be in the wrong place, so the reasoning is up to you.
Q. What board sizes and records are there?
A. Three levels: Easy 5×5, Normal 7×7 and Hard 10×10. The clock starts when you press Start and stops at the solve; your best time per level is kept in your browser, and clear times are ranked separately for each level.