Genshisai (shinto festival of origins) (元始祭)
Genshi-sai Festival (the Shinto festival of origins) is one of taisaijitsu (the days when grand festivals are held) in the prewar public holiday system. Nowadays it is a 'shinsai' (a festival presided over by the emperor himself) held at the Three Shrines in the Imperial Court (Kensho, which is also called Kashikodokoro [the Imperial Sanctuary], Korei-den [the Imperial Ancestors' Shrine], and Shinden [Shrine]) on January 3 in the Gregorian calendar to celebrate the origin of the Imperial throne.
Genshisai originated from chinsai (religious ceremony to appease the gods) which was performed at Hasshinden (eight shrines) of the governor of Jingikan (department of worship) on February 3, 1870 for appeasing Hasshin (the god), Tenjin chigi (the gods of heaven and earth), and imperial ancestors. The form of Genshisai changed to the current form of sanden (three shrines) shinsai on January 3, 1873. Genshi-sai Festival was added to taisai (grand festivals) in accordance with the 'Koshitu Saishi Rei' (the Ordinance of Imperial Household Religious Rites), which was established in 1908 as one of the 'Koshitsu-rei' (The Imperial Household Orders), and it became a public holiday in 1927. After World War II, it was excluded from public holidays, but its ceremony is still performed at the Imperial Court as it was in the past.