What is Yajilin?
Yajilin is a logic puzzle from Nikoli, the Japanese publisher behind Sudoku, Kakuro, and a long list of other pencil puzzles. You shade cells according to arrow clues, then draw a single loop through everything that's left. It's part constraint satisfaction, part path-finding, and it's been a regular at the World Puzzle Championship since 1999. You might also see it written as yajilin-kazuoku, or called Arrow Ring in English. (And yes, people misspell it as "yajlin" or "yajirin" all the time — it's one of those names.)
How to play yajilin
Read the arrow clues
Each arrow clue shows a direction and a number. The number tells you exactly how many cells must be shaded in that direction from the clue.
Shade the cells
Mark cells as shaded based on the arrow clues. Shaded cells cannot touch each other horizontally or vertically — diagonal adjacency is fine.
Draw the loop
Connect all remaining unshaded, non-clue cells with a single continuous loop. The loop travels horizontally and vertically through cell centres — no diagonals, no branches.
Complete the puzzle
When every arrow clue is satisfied, no shaded cells touch, and the loop passes through all remaining cells, the puzzle is solved. Every yajilin puzzle has exactly one solution, discoverable through logic alone.
Where does yajilin come from?
Yajilin first appeared in issue #86 of Puzzle Communication Nikoli in 1999. The name is a contraction of yajirushi (arrow) and rinku (link), which is a pretty accurate description of what you're doing. Outside Japan it sometimes goes by Arrow Ring. It's been a fixture at the World Puzzle Championship ever since, usually sitting in the rotation alongside Sudoku and Nurikabe.
The best way to play yajilin
Loopr is built for yajilin. Drag to draw loop segments, tap to shade cells. The interface gets out of the way so you can focus on the puzzle.
- Over 1,000 handcrafted yajilin puzzles across Easy, Medium, and Hard
- Daily yajilin challenges with streak tracking
- Smart hints that guide without spoiling
- Works offline — no internet required
- No ads, no in-app purchases
Ready to try yajilin?
Download Loopr and start solving today.