Shikaku is a logic puzzle with simple rules and challenging solutions.

The rules of Shikaku are simple.
You have to divide the grid into rectangular and square pieces such that each piece contains exactly one number, and that number represents the area of the rectangle.
Are you lost? Check out the step by step tutorial

Tap/click and drag to draw a rectangle.

Zooming
Pinch with two fingers to zoom in/out. If you use a mouse you can use the scroll button.

Moving
Pinch with two fingers and drag to move the puzzle. If you use a mouse you can click and drag with the middle (scroll) button.

Game modes and sizes

• You can change the game you play from the "hamburger" menu at the top-right corner.
• You can change the mode / size of the current game from the top menu (click on the down arrow at the top/middle)
• There are 2 modes which you can play
  • Random - this mode loads a random puzzle from the chosen size
  • Quest - this mode requires you to login. You can then solve a sequence of puzzles with increasing difficulty.

Other helpful tips

• You can get rid of the address bar and gain extra playing space by dragging the header or the footer quickly upwards so you scroll the page a bit down. It's tricky and you need practice. iOS8+ users - this will be just temporary until you click something in the bottom bar - sad story I know.
• If you are left handed or just playing with your left hand there is a spacial option in the settings just for you.
• Try the different helpers in the settings - some will make the puzzle too easy for you, others may automate some trivial tasks.