Most scholars agree that the purported founding date of Japan (660 BCE) and the earliest emperors of Japan are mythical. This does not necessarily imply that the persons referred to did not exist, merely that there is insufficient material available for further verification and study. Dates in the before the late 7th century were likely recorded using the
Genka calendar system. For those monarchs, and also for the Emperors
Ōjin and
Nintoku, the lengths of reign are likely to have been exaggerated in order to make the origins of the imperial family sufficiently ancient to satisfy numerological expectations. It is widely believed that the
epoch of 660 BCE was chosen because it is a "xīn-yǒu" year in the
sexagenary cycle, which according to
Taoist beliefs was an appropriate year for a revolution to take place. As Taoist theory also groups together 21 sexagenary cycles into one unit of time, it is assumed that the compilers of assigned the year 601 (a "xīn-yǒu" year in which Prince Shotoku's reformation took place) as a "modern revolution" year, and consequently recorded 660 BCE, 1260 years prior to that year, as the founding epoch.
Kesshi Hachidai For the eight emperors of Chapter 4, only the years of birth and reign, year of naming as Crown Prince, names of consorts, and locations of tomb are recorded. They are called the
Kesshi Hachidai (", "eight generations lacking history") because no legends (or a few, as quoted in
Nihon Ōdai Ichiran) are associated with them. Some studies support the view that these emperors were invented to push Jimmu's reign further back to the year 660 BCE. itself somewhat elevates the "tenth"
emperor Sujin, recording that he was called the
Hatsu-Kuni-Shirasu (": first nation-ruling) emperor. == Influences ==