It is recorded in the Kiki that Yūryaku was born to Oshisaka no Ōnakatsuhime (忍坂大中姫) sometime in 417 or 418 AD, and was given the name Ōhatsuse no Wakatakeru[c] (大泊瀬稚武皇子).

[6] In 463, Yūryaku Tennō invited the thunder god of the Mimuro hill to come to the Imperial Palace, and ordered Chiisakobe no muraji Sugaru to fetch the deity.

He obliged, thinking the supernatural being would have no reason to refuse the invitation, and rode carrying a halberd with a red banner, symbolising his office of royal messenger.

Soon enough, the thunder struck, and Sugaru enlisted the help of priests to enshrine the kami into a portable carriage, to be brought in the Emperor's presence, as a great serpent.

This story is recorded in Nihongi and mentioned by William George Aston, in "Shinto, the Ancient Religion of Japan" as well as several other books.

[10][17] Scholar Francis Brinkley lists Emperor Yūryaku under "Protohistoric sovereigns" where he remarks that while some historians have described him as an "austere" man, "few readers of his annals will be disposed to endure such a lenient verdict.

"[15] Scottish Orientalist scholar and journalist James Murdoch regards Yūryaku as a "much maligned person who was a strong if somewhat ferocious ruler.

"[6] British academic and author Richard Ponsonby-Fane noted that the Emperor is described as a "mighty hunter" as its recorded that the God "Hitokotonushi" accompanied him in the chase.

Factors such as "the disproportion between the triggering events", "the violence expressed by the emperor on such occasions (quite extreme in degree)", and the "frequent occurrence of such descriptions" were then considered for a conclusion.

[18] Archaeological research has also confirmed that large keyhole-shaped tombs belonging to the chiefs of local ruling families disappeared from around the end of the 5th century when Yūryaku reigned.

King Waka Takiru in the transcription is thought to be the same person as Ōhatsuse-wakatakeru-no-mikoto as mentioned in the Nihon Shoki, an alias of Emperor Yūryaku.

[30] If Yūryaku's name can be corroborated to this sword then it can be interpreted that the power of the Great King had already extended from Kyushu to Togoku by the latter half of the 5th century.

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

The full context of this latter passage describes how Bu's ancestors conquered countries, and expanded their power to the east and west.

Although the kings of Wa repeatedly requested that the Emperors of the Song dynasty recognize their military control over Baekje, their efforts were denied.

By not offering recognition the Song Emperors could put the Northern Wei in check, and avoid opposition from Goguryeo which was in conflict with Wa.

[36] Scholar Francis Brinkley notes that the power of the Koma clan (supported by the Liu Song dynasty) in Goguryeo increased steadily during this time.

This is solely based though, on the description in the title of Shoban Shokugu Illustrated Scrolls (諸番職貢図巻) included in Ainichi Ginro Sho Ga Zuroku (愛日吟盧書画続録).

While the actual site of Yūryaku's grave is not known, this regent is traditionally venerated at a memorial Shinto shrine (misasagi) in Habikino, Osaka.