Rules: Find a single closed loop passing through each of the black and white circles. The path connects the centers of adjacent cells, and can only make turns of 120°. When passing through a black circle, the path must turn and extend at least two cells in both directions. When passing through a white circle, the path must go straight and must make a turn in at least one of the adjacent cells.
Background: In USPC 2010, there was a puzzle by Dave Tuller that is Hex Masyu. It seemed as a brilliant idea, so I prepared one for 19th WPC – Poland. I haven’t seen this type frequently. In LMD 2013 Qualification, it appeared with branches, you can see the practice puzzle by James.