Castle Wall by JinHoo Ahn
or solve online (using our beta test of Penpa-Edit tools in linex mode where left click+drag draws lines and right click marks X’s)
Theme: Black Box
Author/Opus: This is the 57th puzzle from our contributing puzzlemaster JinHoo Ahn.
Rules: Standard Castle Wall rules.
Difficulty: 2.5 stars
Time Standards (highlight to view): Grandmaster = 2:00, Master = 3:45, Expert = 7:30
Solution: PDF and solving video.
Note: Follow this link for more Castle Wall puzzles. If you are new to this puzzle type, here are our easiest Castle Wall puzzles to get started on. More Castle Wall puzzles can be found in our beginner-friendly collection Intro to GMPuzzles as well as the larger collection Castle Wall, both by Serkan Yürekli.
Wow, this is very nice. Unexpected use of “global” logic here!
Indeed! Very interesting logic.
Love this one.