A free, browser-based logic puzzle — no account, no install, no fuss.
Shikaku (四角に切れ, meaning "divide by box") is a Japanese logic puzzle invented by Nikoli, the puzzle publishing company responsible for popularizing Sudoku. The puzzle was introduced in 1989 and has since become a staple of logic puzzle books alongside Sudoku, Nurikabe, and Kakuro.
The premise is elegant: you're given a rectangular grid with numbers placed in certain cells. Your task is to partition the entire grid into non-overlapping rectangles such that each rectangle contains exactly one number, and the rectangle's area equals that number. Every valid Shikaku puzzle has a unique solution reachable by pure logic — no guessing required.
What makes Shikaku particularly satisfying is its clean aesthetic: the rules are simpler than Sudoku, the grid structure is immediately intuitive, and solutions feel inevitable once you find them. The puzzle scales naturally from beginner-friendly grids that practically solve themselves to sprawling extreme puzzles that can take an hour of concentrated effort.
PlayShikaku.com is an independent browser game built to be the best free place to play Shikaku online. The game combines a verified built-in library with an optional generator. Its foundations are:
The site is designed to be fast, clean, and distraction-free. The game loads instantly, works on any device and screen size, and requires no account or login. Your progress is saved automatically in your browser.
PlayShikaku.com is an independent project. Shikaku is a puzzle type popularized by Nikoli; this site is not affiliated with or endorsed by Nikoli.
10 puzzles each at Easy, Medium, Hard, and Extreme, plus three Expert puzzles — no account needed.
Unlock infinite procedurally generated puzzles across all difficulty tiers, including Expert, Insane, and Nightmare.
Stuck? Start with a nudge, ask for an explanation, then optionally reveal a proven rectangle. Hints are tracked in your stats so you can aim for clean solves.
Unlimited undo and redo. Experiment freely — there's no penalty for reconsidering a placement.
Best solve times for each puzzle are saved locally. Beat your own records across every difficulty.
43 achievements tracking solve counts, speed records, hint-free completions, and more.
Close the tab and come back later — your puzzle state is automatically restored.
Everything runs in your browser. No registration, no email, no tracking of who you are.
Puzzle generation on PlayShikaku.com is handled by a Web Worker running entirely in your browser — the server doesn't generate puzzles; your device does. The generator works in several phases:
Generated puzzles must have a unique solution before they are offered for play.
We don't collect personal data. Your puzzle progress, best times, and settings are stored locally in your browser using localStorage. Nothing is sent to any server. See our Privacy Policy for full details.
PlayShikaku.com is free to play. If you'd like to support development, a one-time $2.99 unlock is available from the in-game menu. It opens the complete curated library, the full Expert, Insane, and Nightmare tiers, and infinite puzzle generation.