One night of dryness originated from Hokkaido, Japan. In order to save the fishermen's special methods, the fishermen soaked the fresh fish in 20% salt water, then exposed it to the cold air and dried it overnight. It was different from traditional salted fish and dried overnight. The fragrance is not chai, the oil retained is rich and sweet, and the air drying time actually has its own specifications. It is necessary to have a night, depending on the climate and air volume, it can be delicious