is an ancient ceremony that marks the accession of a new emperor to Japan's Chrysanthemum Throne, the world's oldest continuous hereditary monarchy. Various ancient imperial regalia (three sacred treasures) are given to the new sovereign during the course of the rite. It is the most important out of the Japanese Imperial Rituals.
Enthronement ceremonies
The enthronement ceremony consist of five sub-ceremonies, which are conducted as constitutional functions (国事行為) based on Article 3 of the Constitution of Japan as follows:
Presentation of the Three Sacred Treasures
The first is the simplest, Kenji-tō-Shōkei-no-gi (剣璽等承継の儀), it takes place immediately after the death or abdication of the preceding sovereign. The successor is formally presented with boxes containing two of the three items that compose the Imperial Regalia of Japan: (1) a replica sword representing the sword Kusanagi-no-Tsurugi (lit. "Grasscutter Sword") (草薙劍), though the original is allegedly enshrined at Atsuta Shrine in Nagoya; and (2) the Yasakani no magatama (八尺瓊曲玉), a necklace of comma-shaped stone beads. The third and most important of the items of the regalia is the mirror Yata no Kagami (八咫鏡), which is enshrined in the Ise Grand Shrine as the go-shintai (御神体), or the embodiment of the Sun goddess herself. It is permanently housed in the shrine, and is not presented to the emperor for the enthronement ceremony. Imperial messengers and priests are sent to this shrine, as well as to the tomb-shrines of the four emperors whose reigns immediately preceded his, to inform them of the new emperor's accession.
The three items of the imperial regalia were originally said to have been given by the Sun goddess, Amaterasu, to her grandson when he first descended to earth and became the founder of the imperial dynasty. Unlike other monarchies, Japan has no crown in its regalia. In the 2019 enthronement ceremony, the treasures were presented to the new emperor in the morning of his ascension date. The visits to the Ise Grand Shrine by Imperial messengers and priests, as well as to the tombs of the previous four emperors, continued on as in past enthronements.
The first audience after the enthronement
The second is called Sokui-go-Choken-no-gi (即位後朝見の儀). The new emperor will meet the three chiefs of the tripartite political system as the representatives of citizens for the first time.
Proclaiming enthronement at the main palace
The third part of the ceremony, called Sokuirei-Seiden-no-gi (即位礼正殿の儀), is the ritual to proclaim and congratulate the enthronement. It is the core part; the last such ceremony was held on October 22, 2019, for Naruhito.
This ancient rite was traditionally held in Kyoto, the former capital of Japan; beginning in 1990, it is done in Tokyo. The 1990 enthronement of Akihito was the first to be covered on television, and have Imperial Guards in political traditional uniforms. It was done indoors, with the elevated stand placed inside the Imperial Palace complex. Only part of the ritual is public, and the regalia itself is generally seen only by the emperor and a few Shinto priests. First came a three-hour ceremony in which the new emperor ritually informed his ancestors that the enthronement is about to take place. This was followed by the enthronement itself, which takes place per tradition in an enclosure called the Takamikura, containing a great square pedestal upholding three octagonal pedestals topped by a simple chair. This was surrounded by an octagonal pavilion with curtains, surmounted by a great golden Phoenix. At the same time, the empress, in full dress regalia, moved to a smaller adjacent throne beside her husband's. Traditional drums were, at this point of the ceremony, beaten to start the proceedings.
The new emperor proceeded to the chair, where after being seated, the Kusanagi, Yasakani no Magatama, privy seal and state seal were placed on stands next to him. A simple wooden sceptre was presented to the emperor, who faced his prime minister standing in an adjacent courtyard, representing the Japanese people. The emperor offered an address announcing his accession to the throne, calling upon his subjects to single-mindedly assist him in attaining all of his aspirations. His prime minister replied with an address promising fidelity and devotion, followed by a "three cheers of Banzai" from all of those present. The timing of this last event was precisely synchronized, so that Japanese around the world could join in the "Banzai" shout at precisely the moment that it was being offered in Kyoto or in Tokyo.