How to play
Shikaku
Make room.
One rectangle at a time.
A few numbers. One whole space to fit together. Start with six little squares.
That is what the 6 is asking for.
Reading view keeps every example and its explanation together, without motion.
Six is an amount of space.
A number tells you how many little squares belong inside its rectangle. Count these six as they join up.
Three across. Two down. 3 × 2 = 6.
What does this 6 tell you?
Choose an answer to check your reason.
Read the answer
Yes. Count the squares inside: three across and two down make six. The number gives the area.
Count the squares inside, not the length of the outline.
Same six. A different fit.
Keep the 6 in place. Move the same six squares into two columns and three rows. Still six.
Both shapes have the right area. We need the rest of the grid to know which one belongs.
A second shape, still six squares.
These are shape studies, not proved puzzle moves. A 1 × 6 strip also has area six.
Now give every square a home.
The sheet opens into our whole puzzle. Each rectangle needs exactly one clue, and its area must match that clue.
Stay inside the grid. No overlaps, no holes. We have not placed anything yet.
The tall shape has six squares. Can it stay?
Choose an answer to check your reason.
Read the answer
Exactly. Both 6s would be inside one rectangle. Each rectangle must contain exactly one clue, even when the two clues show the same number.
Dashed outlines are possibilities. Solid outlines will mark proved placements.
Right area. Wrong company.
The top-left 6 sits in a corner. A 1 × 6 or 6 × 1 strip leaves this five-square grid.
Try 2 × 3: it swallows the other 6. Only 3 × 2 fits without a second clue. Now we can place it.
Dashed: a candidate to check, not a placed rectangle.
A locally tempting shape fails if it contains another clue.
One patch makes room for the next.
The lower-left 6 also needs six squares. A tall 2 × 3 shape cannot start higher: the first rectangle is in the way.
Shift it right and it takes in the 3. A wide 3 × 2 also hits the first patch or takes in the 3. Only the lower-left 2 × 3 remains.
Dashed: a candidate to check, not a placed rectangle.
The first rectangle stays. Its edge is now a fact we can use.
The three has one way through.
A 3 is a strip: 1 × 3 or 3 × 1. Upwards, it hits the first patch. Downwards, it takes in the 2.
Across it goes. The left patch blocks any start farther left. Row 3, columns 3–5, is the only place left.
Dashed: a candidate to check, not a placed rectangle.
The dashed vertical strip shows why “down” fails before we draw “across”.
An edge becomes an answer.
The upper-right 4 cannot be a thin strip: down crosses our 3, and left crosses the first 6.
Try a 2 × 2 square. One row too low overlaps the 3. Slide it up: the top-right corner is its only fit.
Dashed: a candidate to check, not a placed rectangle.
A proved rectangle changes what its neighbours can do.
Equal sides are welcome.
Look at the 4 in the bottom-right corner. A strip up would contain the other 4; a strip left would contain the 2.
Its 2 × 2 square has just one clue. That is the only fit. A square is a rectangle too.
Dashed: a candidate to check, not a placed rectangle.
Two squares are still empty. How must the 2 fit?
Choose an answer to check your reason.
Read the answer
Yes. The empty pair is in column 3, rows 4 and 5. A sideways rectangle would overlap the lower-left 6 or the bottom-right 4.
Four squares inside, one clue, no overlap. Equal sides are allowed.
Everything finds its place.
Two squares remain around the 2. Sideways would overlap a neighbour. Together, vertically, they make its last rectangle.
Six rectangles. Each clue matches its area. Every square belongs, and nothing overlaps. You have proved the whole print.
All twenty-five squares are covered, exactly once.
The seams become the picture only after the last deduction.
Fit your own first puzzleA fresh space.
Yours to fit.
A different 5 × 5, with nothing placed for you. Start small: what shape does the 1 need?
Practice stays here while this page is open. Your regular games and saves are separate.
0 of 25 squares fitted5 × 5
Choose two opposite corners. A 1 uses the same square twice.
Choose a first corner, then the opposite corner. Your rectangle includes both squares.
Clear your rectangles and start a fresh attempt? You can undo the reset.
How to draw a rectangle
Tap or click two opposite corners, in either order. You can start on an empty square. Tap the same square twice for a 1 × 1. With a mouse, the preview follows your pointer after the first click.
Keyboard: Tab into the board. Arrow keys move. Enter or Space selects each corner. Escape cancels. Delete or Backspace removes the rectangle under the focused square. Tab leaves the board.
To resize, draw a new rectangle around the same clue. To remove, select a square in it and choose Erase rectangle. A shape with the right area can still block a later move: use Undo or ask for an explanation.
There is room
for a little logic.
Count the area. Check the company. Let each fitted rectangle help the next. A new grid is waiting whenever you are.
Play Shikaku Return to your practiceFree to play. No account needed.
The quick rules.
- Split the whole grid into rectangles. Squares count too.
- Each rectangle contains exactly one number.
- That number gives its area: how many unit squares are inside. A 6 can be 3 × 2 or 2 × 3.
- Stay inside the grid. Rectangles cannot overlap, and every square must be covered.
A couple of good questions.
Does a clue have to sit in a corner?
No. It can be anywhere inside its rectangle. The top-left 6 in our worked puzzle happens to sit at the edge of the grid, which helps pin its rectangle down.
Can I place any rectangle with the right area?
It must contain exactly one clue and avoid overlap. Even then, it is only a possible placement until you know the rest of the grid can still fit. Compare alternatives before calling a move certain.
Why is this called Shikaku?
You may also see it called Rectangles. The task is the same: divide a numbered grid into rectangles with matching areas.