It can be no exaggeration to state that the products which Japan is so pleased with are in part due to large precision and sharpness of these blades. The origin of umbrellas in Japan is said to become around the Heian period (794 - 1185), once they were introduced from https://andredawto.uzblog.net/indicators-on-traditional-japanese-craftsmanship-you-should-know-49904736