Hills of Silver Ruins (1/5)

Wagen (和元) is the gengou (era name) of the late Emperor Kyou, which continued after his death until Gyousou was formally enthroned. Koushi (弘始) is the nengou chosen by Gyousou.

The gengou (元号) or nengou (年号) dating system begins with an era name created specifically for the reign of that emperor. The year of the enthronement counts as year one. The era name of Youko's dynasty is Sekiraku (赤楽). The kanji refer to the color red and the first character of Rakushun's name.

In Japan, the current era name is Reiwa (令和), and its announcement last year was a major public event. Emperor Naruhito was enthroned in 2019 so 2020 is Reiwa 2.

The Ministry of Winter (冬官) is in charge of public works.

A shoku (蝕) is a wormhole between two universes. Or as Rakushun explains in Shadow of the Moon, "[A] shoku is when here and there get tangled up together." Shoku can be engineered on purpose by a wizard or kirin, as with Youko, but also occur at random, as with Suzu in A Thousand Leagues of Wind.

The Divine Decrees (太綱) are a fusion of constitutional and natural law. Laws promulgated by the emperor must align with the Divine Decrees. Violations have drastic consequences. The most common manifestations of imperial wrongdoing are that youma proliferate and the kirin falls ill (the shitsudou).

If the kirin dies from the shitsudou, the emperor will die too.

Hourai (蓬莱) is a mythical paradise derived from the Chinese legend of Penglai. It is also a classical geographical name for Taiwan, which in the Twelve Kingdoms has come to mean Japan.