Yajilin (Castle Wall) by JinHoo Ahn
or solve online (using our beta test of Penpa-Edit tools)
Theme: Open Middle
Author/Opus: This is the 16th puzzle from our new contributing puzzlemaster JinHoo Ahn.
Rules: Variation of Yajilin rules. Instead of their usual meaning, interior clues refer to the total sum of the lengths of loop segments in the given direction. (An equivalent way to understand these values is to count the number of cell borders crossed by the loop in that direction.)
See also this example:
Difficulty: 3 stars
Time Standards (highlight to view): Grandmaster = 3:15, Master = 6:00, Expert = 12:00
Solution: PDF; a solution video (with info on an Easter Egg for this puzzle) is also available here.
Note: Follow this link for classic Yajilin and this link for Yajilin variations. If you are new to this puzzle type, here are our easiest Yajilin to get started on. More Yajilin puzzles can be found in The Art of Puzzles 2, in Yajilin by Murat Can Tonta and Prasanna Seshadri, and in our beginner-friendly book Logic Puzzles 101.
Amazing! It looks like there’s not enough clues, but the variation rule is very powerful.