Frequently Asked Questions
Everything you need to know about Loopr.
What is yajilin?
Yajilin (sometimes misspelled yajlin) is a logic puzzle from Nikoli, the Japanese company that popularised Sudoku. You shade cells based on arrow clues and draw a single loop through all remaining cells. Every puzzle has exactly one solution, and you can solve it through pure logic — no guessing.
Is yajilin like Sudoku?
Both come from Nikoli, both have a single solution, and both are solved through pure logic. But yajilin is more spatial — instead of filling numbers into a grid, you're shading cells and drawing a loop. If you like Sudoku, you'll probably like this too.
Where does yajilin come from?
Nikoli, the Japanese puzzle publisher that popularised Sudoku, first published it in 1999. The name is a contraction of yajirushi (arrow) and rinku (link). It's been a regular at the World Puzzle Championship since.
What is Loopr?
It's a yajilin puzzle app. Shade cells based on arrow clues, draw a loop through what's left. Over 1,000 puzzles, daily challenges, no ads.
How do I play?
Tap cells to shade them, then drag to draw loop segments between unshaded cells. Arrow clues tell you how many shaded cells lie in that direction. Shaded cells can't touch each other, and the loop must pass through every unshaded cell. There's a full interactive tutorial in the app.
Is there any guessing involved?
No. Every puzzle has exactly one solution, reachable through logic alone. If you're stuck, there's a deduction you haven't spotted yet — try the hints.
What are the daily challenges?
Every day you get three new puzzles: Easy, Medium, and Hard. Complete them to maintain your streak. Daily puzzles are the same for everyone worldwide.
How do hints work?
Hints guide you toward the solution without spoiling it. The first hint highlights any errors. Further hints help you find the next logical move.
Does it work offline?
Yes! All puzzles are included in the app. Play anywhere without an internet connection.
What is the Gauntlet?
The Gauntlet is a weekly challenge featuring one large, demanding puzzle. You have a full week to draw every line and shade every cell.
Is there advertising?
No. Loopr has no ads, no interruptions, and no in-app purchases. Just puzzles.
What devices are supported?
Loopr is available for both iOS and Android.