Drag to draw a rectangle · right-click or Erase to remove it
Each rectangle needs exactly one number, equal to its area
Shikaku means "division" in Japanese, and that's exactly the job: split a grid into rectangles, one per number, until nothing is left uncovered. It was invented in 1989 by Yoshinao Anpuku, a student at the University of Kyoto, and published by Nikoli - the same magazine behind Sudoku and Kakuro. There's no digit-filling here; you're reasoning about area, factor pairs, and which shapes a number can and can't make.
If the rules feel familiar, it's because a version of Shikaku showed up inside LinkedIn in 2026 as a daily mini-game called Patches, designed by puzzlemaster Thomas Snyder. Patches adds shape badges - square, wide, tall, or freeform - on top of the area clues. This site plays it straight: plain numbers, plain rectangles, no daily limit, and no account required.
Three difficulty levels are built in. Easy runs on a 5×5 board, a fair warm-up or a good one to hand to a curious kid. Medium (7×7) is where you start working two or three rectangles out by elimination before the rest fall into place. Hard (10×10) rewards knowing a number's possible shapes before you touch the mouse. Every puzzle here has exactly one valid solution - if you're stuck, the missing rectangle is provable, not a guess.
Every numbered cell is the seed of a rectangle. The number is the exact area - width × height - that rectangle must cover.
Click and drag across the grid to draw a rectangle around a clue. The preview turns red if it would overlap one you've already placed.
Each rectangle must contain exactly one numbered cell - never zero, never two.
Together, the rectangles must cover every single cell in the grid exactly once.
Right-click any rectangle to remove it, or switch on Erase mode and drag across several to clear them at once.
Shikaku is a Japanese logic puzzle invented in 1989 by Yoshinao Anpuku, then a student at the University of Kyoto, and published by the puzzle magazine Nikoli. You divide a grid into rectangles so each one contains exactly one number, and that number equals the rectangle's area.
They share the same foundation. Patches, released by LinkedIn in 2026, is built on classic Shikaku but adds shape badges - square, wide, tall, or freeform - and some clues without a number at all. This site keeps the original ruleset: one number, one rectangle, nothing else.
A rectangle is confirmed correct once the whole puzzle is solved - every cell covered once, every rectangle holding exactly one number equal to its own area. A shape can look right on its own and still be wrong if it boxes out a neighboring clue.
A well-formed puzzle has exactly one solution. Every board here is built to have a single valid arrangement, so if two shapes both seem to fit, one of them breaks something elsewhere on the grid.
Start with numbers that have the fewest possible shapes - primes like 5 or 7 can only form a straight line, and clues near an edge or corner have fewer directions to expand into. Lock those down first; the rest of the board usually follows.
No account or server storage is involved. Your theme choice is saved locally in your browser, but puzzle progress resets if you leave the page - each puzzle is short enough to finish in one sitting.
Yes - no signup, no paywall, and no daily limit. Play as many puzzles as you like across all three difficulty levels.