Chinkon-sai Festival (mass or ceremony for the repose of a soul) (鎮魂祭)

Chinkon-sai Festival is a ritual ceremony for the repose of an emperor's soul on the day before Niname-sai (the Harvest Festival). This ceremony is performed at the Ryokiden, which is a hall located close to the Three Shrines in the Imperial Court. It is also performed at Isonokami-jingu Shrine on the same day. When the ceremony is performed for an emperor, it is referred to as 'Mitama Shizume' or 'Mitama furi' which means calming a soul. Chinkon-sai Festival used to be performed on the second Day of the Tiger of November in the old calendar (on November 22 after the solar calendar was introduced). Since it is the day of the winter solstice when solar energy becomes the weakest, the ritualistic ceremony was probably performed to enhance the energy of an emperor's soul who was deemed a descendant of Sun-goddess Amaterasu. Chinkon-sai Festival also means a ceremony to enhance the soul of an emperor who is going to conduct a significant festival called Niiname-sai Festival (which means "the Harvest Festival," and the emperor's first Niiname-sai Festival is specially referred to as Daijo-sai Festival). This ceremony has been performed for the Empress, the Crown Prince, and the Crown Princess after World War II.

Ukifune no Gi (ceremony of ukifune)

A ceremony called 'Ukifune no Gi' is performed as a part of Chinkon no Gi (a ritual ceremony for the repose of a soul). The 'Ukifune no Gi' is a ritual ceremony in which a court lady stands on a turned-over container called ukifune and she strikes the bottom of the container ten times with a long-handled spear. This originated from one scene of Japanese Mythology; where Amenouzume (goddess of entertainment) climbed up onto the container and danced when the Sun-goddess Amaterasu hid in the cave.
The "Kogo-shui" (the History of the Inbe clan) says, 'the outline of Chinkon no Gi is the remains of Amenouzume no Mikoto.'
This ritual ceremony was once also called 'Sarumenokimi no chinkon' (the repose of a soul by the Sarumenokimi clan) because it was performed by women from the Sarumenokimi clan, who was said to be the descendant of Amenouzume no Mikoto.

Tamafuri no gi (ritual ceremony for the repose of a soul)

After Chin kon no gi, Tamafuri no gi, in which the dress of en emperor is shaken from right to left ten times, is performed. It is said that this originated from an incantation which used ten pieces of sacred treasure which had been granted from Amatsukami (a god of heaven) to Nigihayahi, who was a child of Tenjin (a god of heaven). "Sendai Kujihongi (Ancient Japanese History)" states that umashimaji, a child of Nigihayahi no Mikoto, used ten kinds of votive objects to pray for mental and physical soundness of Emperor Jinmu.
It also states 'so-called mitamafuri no matsuri (mass or ceremony for the repose of a soul) originates from this.'

[Original Japanese]