In the world of noodles, some things don't fit neatly into categories. Japanese harusame 'spring rain', look like bean thread noodles, but are made from potato and corn starches. Shirataki, also Japanese, are fine strands of a jelly-like paste, konnyaku, made from Japanese yam. Shirataki, meaning 'white waterfall', is most commonly used in sukiyaki and sold suspended in water in clear plastic sausage-shaped packaging. Korea's dang myun, a long greyish noodle, is the final wildcard. Made from sweet potato starch, it's particularly chewy and good for soaking up broths.
You'll need to begin this recipe the day before.