A PLACE FOR EVERY RECTANGLE
Shikaku.
A few numbers. One whole grid.
Find where each rectangle belongs.
Puzzle 1 / 36
0 / 7 regions
Choose two opposite corners to draw your first rectangle.
Choose two opposite corners of a rectangle. It must contain exactly one number, and its area must match that number. Fill the board without overlaps or gaps.
Keyboard, touch & region controls
Tab to the board, use arrow keys to move between squares, and Enter or Space to choose each corner. Escape cancels the first corner. On a phone, tap two corners; scrolling and pinch zoom remain available. A mouse can also drag between corners.
Choose a filled square or a region below, then use Remove rectangle. Locally legal placements can still lead to a dead end: Check or Hint can detect a contradiction. Helpers do not change your rectangles until you choose Apply hint.
Undo works for board changes in this tab. After a reload, your saved board becomes the new undo starting point.
36 original puzzles to explore on 5×5, 6×6 and 7×7 grids. Every puzzle is checked for a unique partition and a complete route using our supported deduction rules. Grid size describes the board, rather than a measured difficulty rating. Progress stays in this browser.
NUMBERS BECOME SPACES
How to play Shikaku
Divide the entire grid into rectangles. Each rectangle must contain exactly one numbered square, and its area must equal that number. Rectangles cannot overlap or leave gaps.
- Read an area. A 6 can belong to a 1×6, 2×3, 3×2 or 6×1 rectangle, if the board and other clues leave room. A square is a rectangle too.
- Choose two corners. Select one corner, then the opposite corner to place a rectangle. With a mouse, you can also drag between corners. Use the arrow keys and Enter on a keyboard; Escape cancels a selection.
- Use the whole grid. A rectangle can fit its clue and still block another part of the puzzle. Check your position, undo a move or ask for an explained hint. Cover every cell to finish.
LOOK FOR WHAT CANNOT FIT
Plan a rectangle before drawing it
Start by testing the shapes that each number allows. Then look at cells near an edge or between clues: which rectangle could reach them without taking in a second number?
- Compare possible shapes. The same area can have different dimensions. Board edges and nearby clues can rule shapes out.
- Notice shared cells. If every remaining shape for one clue covers a cell, that cell cannot belong to another clue.
- Keep room for the rest. A locally valid rectangle is a move to test, not a guarantee. Use Check and Undo when the remaining spaces stop fitting.
A LITTLE ROOM TO THINK
Before your next rectangle.
What does the number mean?
It is the area: the number of cells inside that rectangle, including the numbered cell. It does not give the rectangle’s width or height on its own.
Can a rectangle contain two numbers?
No. Every rectangle contains exactly one clue, even if two clues have the same value. The finished rectangles cover the grid once, with no gaps or overlaps.
Does a hint reveal the whole answer?
A hint explains one rectangle that follows from the remaining possibilities. It waits for you to apply it. If your current rectangles conflict with a complete partition or a check cannot finish, the game says so instead of silently changing your moves.
Where do these puzzles come from?
The collection was generated for Brainfold, filtered for unique answers and supported logical deductions, and reviewed for repeated layouts. We do not copy another site’s puzzle boards or claim that a familiar geometric arrangement cannot occur elsewhere. Shikaku’s rules are credited to Nikoli.
Can I play on my phone?
Tap two opposite corners instead of dragging. Select a placed region and use Remove rectangle to erase it. Undo reverses your moves in the current session. Progress is local to this browser; it does not sync between devices.