"Hasshin-den" is the temple where the eight gods protecting the Emperor are enshrined, built under the ritsuryo system in Japan, in the sai-in (western quarter) of the Department of Worship.
By protecting the Emperor, the nation is also protected. Therefore, in some instances, these eight gods were enshrined among people as well. At the ceremony for the repose of the soul, nine gods, these eight gods plus the Onaobinokami, are honored.
According to some old diagrams at the Hasshin-den, the main buildings enshrining each god were independent of one another, and the eight main buildings facing east extended north to south to the northwest of the sai-in in the Department of Worship. There was a vermilion fence surrounding the shrine, 30.3 m from north to south and 9.09 m from east to west, and there were no objects in which the deity resided inside the buildings, but sakaki (species of evergreen sacred to Shinto) was placed inside. Torii (Shinto shrine gate) were erected in front of three locations, from the north, the first shrine, the fifth shrine, and the eighth shrine. Hasshin-den is described in the Engishiki Jinmyocho as 'Mikannagisai kamihachiza' and is considered a renowned shrine.
After it was burnt down during the Onin Rebellion, it was not rebuilt, but in the Edo period, the Yoshida family built a Hasshin-den on the grounds of the Yoshida-jinja Shrine and the Shirakawa family built one on their property as an alternative to the Hasshin-den at the Imperial Court.
With the Meiji Restoration, the Department of Divinities was restored, and in 1869, a temple for Department of Divinities was built and a Senza-sai Festival (festival for transfer of a Shinto shrine) was held. On this occasion, not only the eight gods of Hasshin-den, but also the gods of heaven and earth and the souls of successive Emperors were honored. Prior to this, the souls of successive Emperors were honored at the Kurodo (structure used for private religious observances at the Imperial Palace) in a Buddhist ritual, but Kurodo was abolished thereafter. In September 1872, a decision was made to have only the Department of Divinities perform religious missions, and the Hasshin-den was transferred from the Department of Divinities to the Imperial Court, while the souls of successive Emperors were transferred to the shrine of imperial ancestors in the Imperial Court.
In October of the same year, the eight gods of Hasshin-den were enshrined together with the gods of heaven and earth, and the name 'Hasshin-den' was abolished and renamed 'Shinden.'
Shinden is one of the palace sanctuaries inside the imperial palace. Additionally, among the eight gods, for Omiyanomenokami, a shoshi (small shrine) honoring Omiyanomenokami was built on the historic land of the sai-in at the Department of Worship.