히타치 국
According to the theory proposed by Hakusei Arai, kanji in ancient times were representing pronunciation of the Japanese language, and the original meaning of the kanji does not match the meaning of the words they are describing. Therefore, the words expressed from them only explained pronunciation not the actual meanings. In Koshitsu (古史通), Hakuseki interpreted Takamagahara in hiragana instead of kanji and compared it to Taga Country in Hitachi Province. Also, he suggests that places called “Takaama-no-Ura” and “Takaama-no-Hara” in Hitachi Province are originated from Takamagahara.