“Sotanghon” is also a kind of noodle which similarly looks like “bijon” . (see picture). This is commonly called cellophane noodle, vermicelli noodle or transparent bean noodle (Wikipedia). Here is another tip of producing sotanghon out of mongo beans (mung beans):
1.Soak mongo for four hours.
2. Grind mongo (pulverized mongo fall into a series of filter collecting only the fine liquid mongo).
3.Separate water and take residue by either exposing to sunlight or wrapping in bag.
4.Cook in boiling water.
5.Flour is then “balled” or made into cut paste rolled in dry mongo flour.
6.Put mongo paste in molding machine which is then dropped directly in waiting boiling water.
7.Immediately soak molded paste in cold water then cut into strips.
8.Expose to sunlight to control texture and viscosity.