Nanban trade
Keiran Somen is the name of "Fios De Ovos" in Japan, where it was first made 342 years ago. The restaurant Matsuyariemon has produced their traditional signature "Keiran Somen" for 13 generations. The dessert is one of the "nanbangashi", which are desserts introduced from Portugal in the Nanban trade, and the recipe has been an exhaustively guarded secret passed down from one generation to the next.