How to Solve Rectangles Puzzles
How Rectangles (Shikaku) works and how to solve it: the 1s and 2s, primes in narrow spaces, numbers with only one rectangle and squares only one can reach.
Rectangles is a quiet, satisfying logic puzzle, known in Japan as Shikaku. The grid is scattered with numbers, and you cut the whole grid into rectangles so that three rules hold:
- Every square belongs to exactly one rectangle. No gaps and no overlaps.
- Every rectangle holds exactly one number. Not zero and not two.
- The number is the rectangle's area. A 6 covers six squares: 1 × 6, 2 × 3, 3 × 2 or 6 × 1.
Squares count as rectangles, so a 4 can be a 2 × 2 block and a 9 a 3 × 3 block. The numbers always add up to the number of squares in the grid, and every daily grid has exactly one way to cut it.
Controls on the page
Drag from one corner of a rectangle to the opposite corner: a dashed outline follows your finger or the mouse, and the line above the grid shows its size, such as 3 × 2 = 6 squares, and which number it holds. Let go to draw it. A new rectangle replaces any rectangle it overlaps. Tap a drawn rectangle to take it away, and tap an empty square to draw a single 1 × 1 rectangle. Each rectangle gets a soft colour of its own, and with Show mistakes on, a rectangle with no number, two numbers or the wrong size is striped in red. On a computer, the arrow keys move a cursor, Enter sets the first corner and Enter again the opposite one, Escape lets go of the first corner and Delete takes away the rectangle under the cursor.
Sizes and difficulty
| Level | Grid | Numbers |
|---|---|---|
| Easy | 6 × 6 | areas 1 to 8, about ten rectangles |
| Medium | 8 × 8 | areas 2 to 12, about thirteen rectangles |
| Hard | 10 × 10 | areas 2 to 16, about seventeen rectangles |
Every daily grid is solved by a program using only the techniques below before it is published. On medium and hard days the numbers are then moved, where the techniques still allow it, to squares that leave them more possible shapes, so they take a little more thought.
Start with the small numbers
A 1 is a single square: box it at once. A 2 is a domino, lying down or standing up, and very often one of the two directions is blocked by the edge, another number or a rectangle you have already drawn. A 3 is a straight strip of three, and it has at most six positions, usually far fewer. Clearing the small numbers first gives the big ones walls to lean on.
Primes and narrow spaces
Some areas can only be straight strips: 2, 3, 5, 7, 11 and 13 have no other factors, so their rectangles are always one square wide. A 5 squeezed between the edge of the grid and a row of other numbers often has a single position left. Areas like 4, 6, 8 and 12 have several shapes, but in a narrow corridor most of them stop fitting. For each number, picture each width that divides it and ask whether a rectangle of that width fits without touching another number.
A 5 by the wall
A 5 sits in the top row, two squares from the left edge, with a 3 right below it. A 5 can only be 1 × 5 or 5 × 1. Standing up, it would cover the 3, so it must lie along the top row. It needs five squares in a row that include its own square and no other number: if a 4 sits three squares to its right, the only strip that fits starts at the left edge.
Numbers with only one rectangle
The core of the puzzle is simple: for every number, list the rectangles that could be its own. A rectangle has to have the right area, include the number's square and include no other number. When a number has only one rectangle left, draw it. Every rectangle you draw takes squares away from its neighbours, and their lists shrink in turn.
When a number still has two or three possible rectangles, look at what they share. If every one of them covers a certain square, that square belongs to this number, even before you know the exact shape, and no other number's rectangle may use it.
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Squares only one number can reach
Turn the question round. Take an empty square far from the numbers and ask which numbers could stretch a rectangle over it. Often the answer is a single number: the others are too small, too far or fenced off by rectangles already drawn. That number's rectangle must cover the square, so any of its shapes that miss the square are out. Corners and edges of the grid are good places to ask, because few rectangles reach them.
A routine for every grid
- Box the 1s and 2s that have only one way to go.
- Strips and corridors. Check every prime and every number near the edge.
- One rectangle left? Draw it, then recheck its neighbours.
- Shared squares. Mark squares that all of a number's shapes cover.
- Lonely squares. Find squares that only one number can reach.
- Big numbers last. By now their outline is usually fixed.
Common mistakes
- Forgetting the squares. A 4 can be 2 × 2, a 9 can be 3 × 3 and a 16 can be 4 × 4.
- Leaving a gap. A square left over that no number can reach means an earlier rectangle is wrong. Undo it rather than drawing around the gap.
- Swallowing a second number. Show mistakes stripes such a rectangle red at once.
Scoring and the leaderboard
Rectangles is ranked by time, fastest first; fewer changes break ties. Every rectangle drawn or taken away is a change, so it pays to be sure before you draw. The grid is checked the moment the last rectangle completes it, and only a member's first solve of the day counts for the leaderboard; practice puzzles from Play more are never ranked. If you enjoy this kind of spatial reasoning, Light Up and Picture Cross are good next puzzles.
Play it now
Every game is free in your browser, with nothing to download; the daily puzzles change at midnight and the archive keeps the last 60 days. See all the logic games.
Questions and answers
Is Rectangles the same puzzle as Shikaku?
Yes. Shikaku is the name used in Japan; the rules are the same: cut the grid into rectangles, each holding one number equal to its area.
Can a rectangle be a square?
Yes. Squares are rectangles too, so a 4 can be 2 × 2 and a 9 can be 3 × 3.
Do the numbers always add up to the grid?
Yes. The areas add up to the number of squares in the grid, so the rectangles cover it exactly with nothing left over.
Will I ever need to guess?
No. Before a grid goes out, a solver that knows only the moves in this guide (a number with one possible rectangle, shared squares, lonely squares) has to finish it, which also proves there is only one way to cut it.
Written by the DailyGameClub team from the rules as DailyGameClub plays them. Updated October 26, 2026. New to a word? See the glossary. Spotted a mistake? Tell us.