- Japanese: 新治
- Other names: Nihihari, Niihari
- Etymology: Newly opened
Nihihari (or Niibari) is mentioned numerous times within the Hitachi no Kuni Fudoki. Before Hitachi province (present-day Ibaraki prefecture) was formed in the 7th century (under Emperor Kotoku's reign), the region was made up of six smaller regions, one of which was Nihihari. Mt. Tsukuha is located within.
The aforementioned etymology for Nihihari, "newly opened", evidently springs from the story of Hinarasu the later Kuni no miyatsuko of the region. He was commanded by either Emperor Sujin or Yamato Takeru (sources differ) to create a well. He was given the position of magistrate after being sent against the Emishi of the region.
After the 645 Taika Reform, geographical names were changed to fit the new governmental system. Before the Taika Reform, Nihihari was called Nihihari no Kuni 新治国, but after, it was called Nihihari no Kohori (Koori) 新治郡. Emperor Kotoku's reign coincided with the Taika Reform, which places the creation of Hitachi province and the making of Nihihari as a district therein, at the same general time period.
- Aoki, Michiko Y. Records of Wind and Earth Michigan: Association for Asian Studies, Inc., 1997.
- Funke, Mark C. Hitachi no Kuni Fudoki. Monumenta Nipponica.