The term 'Joshi' or 'Jomi' means the day of the Serpent (the sixth sign of the Chinese zodiac) in the beginning of the month, and it had originally indicated the day of the Serpent in March, but it is reported that, after the Wei dynasty (Three States Period) in ancient China, the Joshi Festival became celebrated on March 3.
「上巳」は上旬の巳の日の意味であり、元々は3月上旬の巳の日であったが、古来中国の三国時代の魏(三国)より3月3日に行われるようになったと言われている。