The Unchangeable Standards - The Unchangeable Standards of the Fox

...The law on imperial succession that Emperor Tenchi established. It is read as "the unalterable law of the common law." It was first seen in the Shoku Nihongi in the accession decree of Emperor Genmei in 707 (Keiun 4), which reads, "The unalterable law of the common law of Emperor Oyamaneko, who reigned in the majestic Otsu Palace in Omi, as long as the heavens and the earth, and as far as the sun and the moon." After that, the modification became simpler, but it was seen in the accession decrees of both Emperor Shomu and Emperor Koken.

*Some of the terminology explanations that refer to "unalterable norms" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…天智天皇の定めたという皇位継承にかかわる法のこと。〈改（かわ）るまじき常の典（のり）〉と読む。《続日本紀》にみえる707年(慶雲4)の元明天皇即位の宣命に，〈関（かけまく）も威（かしこ）き近江の大津宮に御宇（あめのしたしろしめ）しし大倭根子天皇の，天地と共に長く日月と共に遠く，改るまじき常の典〉とみえるのが初見で，以後修飾は簡略になるが，聖武･孝謙の両天皇の即位宣命にみられる。…

※「改るまじき常の典」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報