[6] The Kojiki records that he ruled from the palace of Sakaihara-no-miya (軽之堺原宮, and in the Nihon Shoki as 軽境原宮) at Karu in what would come to be known as Yamato Province.

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

[9] While the actual site of Kaika's grave is not known, the Emperor is traditionally venerated at a memorial Shinto shrine (misasagi) in Nara.

The Imperial Household Agency designates this location as Kaika's mausoleum, and its formal name is Kasuga no Izakawa no saka no e no misasagi.

Historian Louis Frédéric notes this idea in his book Japan Encyclopedia where he says "more likely early AD", but this remains disputed among other researchers.