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2, 3, 5, 7 can only form 1×N rectangles. Place them first — their shape is forced.
A "6" can be 1×6, 2×3, 3×2, or 6×1. Learn which shapes fit where.
Start with smaller grids to build pattern recognition before tackling larger puzzles.
If placing a rectangle blocks another number, it's wrong. Think one step ahead.
Stuck? Enter your puzzle and get the unique solution instantly.
Each rectangle's area must equal its number. No more, no fewer.
A cell numbered "2" on a Shikaku grid is the strongest clue — it can only be a 1×2 or 2×1 rectangle, no thinking required. Start every puzzle by scanning for primes first. Then check if those rectangles reveal new forced placements for neighboring numbers. This "cascade from primes" technique works on every difficulty level and is the single fastest way to speed up your solving.
Read Full Guide →
4×4 grids with guided hints. Learn rectangle placement, area rules, and elimination basics.
5×5 grids with simple shapes. Practice prime numbers and corner strategies at your own pace.
5×6 grids with complex shapes. Master prime numbers, corner strategies, and multi-step deduction.
6×6 grids. Combine multiple techniques and plan several moves ahead.
7×8 grids requiring deep reasoning. Chain eliminations, overlap detection, and forced placements.
10×10 puzzle seeded by date. Same puzzle worldwide — compare your time with friends.
"Finally a puzzle game that's actually relaxing. The cat visuals make it so much more fun than plain number grids. I play every morning with my coffee."
"My 8-year-old loves this! She's learning spatial reasoning without even realizing it. The tutorial levels are perfect for kids."
"I've tried dozens of Shikaku apps. This one has the best UI by far — clean, fast, and the cat expressions when you solve a rectangle are adorable."
"The daily challenge keeps me coming back. Competing with friends on solve time is addictive. 10×10 is no joke!"
"No ads, no paywalls, no nonsense. Just pure logic puzzles. This is how browser games should be made."
"Great brain trainer during commute. Wish there was a dark mode but otherwise perfect. The hint system is well balanced — helps without spoiling."
Play GridPaw anywhere, anytime. Add to your home screen for offline support, no browser bars, and instant launch.
GridPaw is a free Shikaku puzzle game with adorable cat visuals. Draw rectangles on a numbered grid so each rectangle covers exactly the number of cells shown. It's the classic Shikaku (rectangle partition) puzzle by Nikoli — the same company behind Sudoku — reimagined with cats.
Whether you're new to Shikaku or a seasoned solver, GridPaw offers unlimited procedurally generated puzzles across 7 difficulty levels, from Tutorial 4×4 to Legend 8×8. Every puzzle has a unique solution reachable by pure logic — no guessing required.
The rules of Shikaku are simple:
That's it — no math beyond multiplication. The challenge is figuring out which shapes fit where when multiple numbers compete for space.
Rushing to fill cells is the fastest way to get stuck. Instead, work systematically:
Visit our Tips & Strategy page for detailed guides on each technique.
Unlike many puzzle sites, GridPaw has no ads interrupting gameplay, no paywalls, and no registration. Every puzzle is free, every solution is unique, and every solve ends with a cute cat celebration. The Daily Challenge gives you a reason to come back every day with a fresh 6×6 puzzle and streak tracking.
If you enjoy Sudoku, KenKen, or other logic puzzles, Shikaku offers a refreshing change with spatial reasoning instead of arithmetic. The rectangle partition mechanic is easy to learn but rewards deep thinking — perfect for a coffee break or a long session.
Forgetting area constraints: a rectangle around a "4" must cover exactly 4 cells — no more, no fewer. Overlapping rectangles: each cell belongs to exactly one rectangle. Ignoring forced placements: if a number can only fit one rectangle shape, place it first.
