How to Play Step by Step
The clearest first read if you want to understand the puzzle from clue numbers to finished rectangles.
Start hereGuides
Shikaku Guides
Start with the essentials, sharpen your solving, or open a specific topic when you already know what you need.
Recommended
Best Places to Start
These three guides answer the most common first questions, so they sit at the top.
Solve Without Guessing
Use constraints instead of blind choices.
Open guideHow Daily Works
See how Daily differs from Practice and why it fits a routine.
Open guideBrowse
Core Guides
Six clean entry points for the basics, common mistakes, tools, and shared play.
What Is Shikaku
Understand the puzzle before you learn the moves.
Open guideShikaku Rules
The rectangle rules, explained cleanly.
Open guideBeginner Tips
Small habits that make early boards easier.
Open guideCommon Mistakes
The errors that trip up most new solvers.
Open guideHow to Use the Solver
Enter clues correctly and read the results.
Open guideShare with a Friend
Send one exact board instead of a random page.
Open guideMore Topics
Explore by Topic
The rest of the library lives here in lighter lists, so the page stays easy to scan.
Read the Board Better
- Edges, Corners, Small Clues Pattern reading
- Rectangle Validation Check legal shapes
- Unique Solutions Why solver checks matter
Modes and Sharing
- Use the Daily Archive Catch up on missed boards
- Create a Custom Challenge Build a shareable board
Progress and Habit
- Best Beginner Difficulty Choose the right board size
- Focus and Daily Brain Exercise A lighter habit perspective