[9] During his reign local recorders were allegedly appointed for the first time in various provinces, a royal treasury was established, and court waitresses (Uneme) first appeared.

Sometime during the interval before Richū assumed the throne, he sent his younger brother, Prince Suminoe no Nakatsu (住吉仲皇子) to make marriage arrangements for his consort Kuro-hime (黒媛).

[9][4] In the year 403 AD, "local recorders were appointed for the first time in various provinces, who noted down statements and communicated writings of the four quarters.

Its said that the Emperor heard a voice in the wind utter mysterious words in the "great void" before a messenger announced of her death.

[12] Orientalist scholar James Murdoch includes Emperor Richū in the "earliest non-legendary" sovereigns of Japan, while academic Richard Ponsonby-Fane stated that this "may be termed the semi-historical period".

[9][13] Scholar Francis Brinkley lists Emperor Richū under "Protohistoric sovereigns", and notes that rulers from this point forward no longer have reigns of "incredible length".

[14] Richū has also been possibly identified with King San in the Book of Song by Confucian scholars Kenrin Matsushita [ja] (松下見林) and Arai Hakuseki.

Aston states in his reasoning that the arrival of the Korean scholar Wani did not take place until 405 AD, and "[historians] have not yet got down to time of accurate chronologically".

It is certainly possible that he was a chieftain or local clan leader, and that the polity he ruled would have only encompassed a small portion of modern-day Japan.

[16] His name might have been regularized centuries after the lifetime ascribed to Richū, possibly during the time in which legends about the origins of the imperial dynasty were compiled as the chronicles known today as the Kojiki.

[17] While the actual site of Richū's grave is not known, this regent is traditionally venerated at a kofun-type Imperial tomb in Sakai, Osaka.

The Imperial Household Agency designates this location as Richū's mausoleum, and is formally named Mozumimihara Minamisagi (百舌鳥耳原南陵).

[17] Unless otherwise noted (as BC), years are in CE / AD  * Imperial Consort and Regent Empress Jingū is not traditionally listed.