Jimmu's Eastern Expedition

According to the chronicles Kojiki and Nihon Shoki, Jimmu's brothers were born in Takachiho, the southern part of Kyūshū in modern-day Miyazaki Prefecture.

As they reached Naniwa (modern-day Osaka), they encountered another local chieftain, Nagasunehiko (長髄彦, "the long-legged man"), and Itsuse was killed in the ensuing battle.

The record in the Nihon Shoki of Emperor Jimmu states that his armed forces defeated a group of Emishi (蝦夷) before his enthronement.

Upon scaling a Nara mountain to survey the Seto Inland Sea he then controlled, Jimmu remarked that it was shaped like the "heart" rings made by mating dragonflies, archaically called akitsu 秋津.

It is generally thought that Jimmu's name and character evolved into their present shape just before[4] the time in which legends about the origins of the imperial dynasty were chronicled in the Kojiki.