Ashihara no nakatsukuni (葦原中国) (葦原中国)
Ashihara no nakatsukuni is a world which exists between Takamanohara (plain of high heaven) and Yomi (world after death), that is, Japanese soil. It is also called "Toyoashihara no nakatsukuni" or simply "Nakatsukuni".
It is thought to refer to Japanese soil in which human beings live, in contrast to the celestial world Takamanohara in which gods live.
Because lay believers want to interpret mythology as the reflection of historical facts, they generate theories as follows, but academic societies do not take any of them seriously:
The first theory is that Izumo Province itself is Ashihara no nakatsukuni. The second theory is that Ashihara no nakatsukuni (described as 葦原中国 in Japanese) is the origin of the word "the Chugoku region" (described as 中国地方 in Japanese) including Shimane, Tottori, Hiroshima, Okayama and Yamaguchi Prefectures. The third theory is that because Yamato was an area controlled by the Izumo forces and was called Ashihara no nakatsukuni before Jimmu tosei (Eastern expedition of the Emperor Jinmu), the anti-Izumo forces called all the areas controlled by the Izumo forces Ashihara no nakatsukuni.
The fourth theory is that as Yamato sovereignty (the ancient Japan sovereignty) was transferred eastward and established there, Takamanohara became the sovereignty's former sphere of influence or the Kyushu region, and Ashihara no nakatsukuni became Kinai region (provinces surrounding Kyoto and Nara).
The fifth theory is that Kokai, the plain of later the Yamato basin and the vicinity of Mt. Miwa were named Ashiharamizuho no kuni, and present-day around Kashihara was named Ashiwara no nakatsukuni or 葦原中国 in Japanese.
The sixth theory is that "nakatsu" means Nakatsu City, Oita Prefecture.