( – 571 AD) is the first for which contemporary historiography has been able to assign verifiable dates. The conventionally accepted names and dates of the early Emperors were not confirmed as "traditional" until the reign of Emperor Kanmu between 737 and 806 AD. Previously the Japanese archipelago had been a confederation of powerful ruling families from various regions. This appeared to have changed with the appearance of Emperor Yuryaku as the autocratic rule of the Great King was established and a centralized system centered on the Great King began. This is further supported by a major discovery that occurred in 1968 when the iron Inariyama burial-mound sword was extracted from a tomb. In 1978, X-ray analysis revealed a gold-inlaid inscription that comprises at least 115 Chinese characters. The given year on the sword is denoted as "xin-hai" ("Year of the Metal Pig") according to the Chinese sexagenary cycle, in which the name of the year is recycled every 60 years. While this year is generally regarded in Japan to correspond to 471 AD, at least one historian suggests that 531 is a more likely date.
The person buried in the tomb is given the name "Wowake", who was thought to be an influential warrior in the region. 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. As each inscription contains the name of an official position, this suggests that a system similar to the Bemin was already in place. While the Eta Funayama Sword also apparently mentions the name "Waka Takiru", many characters on that sword are illegible possibly due to polishing by a Japanese sword sharpener at the end of the Taisho period. 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.
There is no evidence to suggest that the title tennō (meaning "emperor") was used during the time to which Yūryaku's reign has been assigned. Instead, his title could have possibly been , meaning "the great king who rules all under heaven", or "Great King of Yamato". The name Yūryaku-tennō was more than likely assigned to him posthumously by later generations. 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.
King Bu
thumb|200px|Goguryeo in 476 AD
It is theorized that Emperor Yūryaku may be synonymous with King Bu () as written in the Chinese records. According to the Book of Song, Bu dispatched envoys to Emperor Shun of Song (a Southern Chinese dynasty) in both 477 and 478 AD. The first envoy was to inform the Chinese emperor that King Kō (Emperor Ankō) had died, and his older brother had become king. It is written that he called himself "King of Wa", and the military commander of several different Kingdoms. It is written that in the following year Emperor Shun appointed Bu the title of Grand Peacekeeper-General of the East. The full context of this latter passage describes how Bu's ancestors conquered countries, and expanded their power to the east and west. It describes how they crossed the sea to the north and reached the southern part of the Korean Peninsula. Although the kings of Wa repeatedly requested that the Emperors of the Song dynasty recognize their military control over Baekje, their efforts were denied. The reason for this is thought to be that the Song dynasty placed importance on Baekje, which was located in a strategically important area. 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. Scholar Francis Brinkley notes that the power of the Koma clan (supported by the Liu Song dynasty) in Goguryeo increased steadily during this time. Brinkley suggests that Emperor Yūryaku's attempts to establish close relations with the Chinese Emperor seem to be from a desire to isolate Korea, which ended in failure. Japanese historian Mori Kimiaki points out that both of these appointments coincide with the founding year of their respective dynasties. This is thought to be an administrative matter, and it is not clear whether King Bu (Yūryaku) himself requested it or not. There is at least one theory that supports the envoy being sent to Southern Qi in 479 as being factual. This is solely based on the description in the title of included in . Yūryaku is also enshrined at the Imperial Palace along with other emperors and members of the Imperial Family at the Three Palace Sanctuaries. He is additionally deified at the in Gose, Nara.
Consorts and children
Spouse/Concubine
{| class="wikitable"
|-
! Position || Name || Father || Issue|
| Emperor Nintoku
| align="center"| None
|-
| Consort<br>(Hi)
|