1
Pick a board size
Start with 6 x 6 for quick rounds, then move up to larger boards when you want more scanning and longer solves.
Practice Mode
Practice
Timer
00:00
Select a rectangle that contains exactly one number and matches its area.
Low-pressure practice mode. Timing starts on your first move. Results are stored in this browser only.
How to Play
2
Drag a rectangle
Select an axis-aligned block that contains exactly one clue cell. The clue tells you the area that rectangle must cover.
3
Match the area cleanly
The rectangle area must equal the clue number. Each rectangle can include only one clue, and overlapping placements are removed.
4
Fill the board
When every cell is covered by valid rectangles, the round finishes automatically and the result is saved to your local practice history.
Why Practice
Shikaku is a clean logic puzzle. There is no arithmetic to brute-force and no guessing benefit. You read the board, test structure, and slowly compress uncertainty until every rectangle has one correct place.
This Practice page is intentionally lightweight. It gives you instant replay, simple stats, and size-based sessions for warm-ups, casual rounds, and longer board solving without ranked pressure.
Example Puzzle
Look for forced rectangles first. Small clues such as 2 and 3 usually have very few valid shapes, so they narrow the board quickly.
Large clues become easier once nearby cells are claimed by smaller confirmed rectangles.
Frequently Asked Questions
Does Practice save my progress to a server?
No. Practice stats and recent puzzles stay in local browser storage.
Why did a rectangle disappear when I placed another one?
The current version treats overlap as an edit flow. Any overlapping rectangles are removed before a new valid rectangle is committed.
What changes between the practice levels?
Each level currently maps to a larger board size from 6 x 6 up to 10 x 10. Bigger boards create more clue interactions, longer scans, and more rectangle placements.
Can I play on mobile?
Yes. The board supports drag interactions and tap-start, tap-end rectangle selection on smaller screens.
Daily Challenge
One puzzle per day, one official completion record, one local streak.
Play today's puzzleSolver
Paste clue layouts, check solvability, and reveal one valid rectangle partition when you get stuck.
Open solverArchive
Historical packs and filtered puzzle collections are planned after MVP validation.
See roadmapAbout
Read the product direction, current scope, and what the lightweight first release is optimizing for.
Learn more