May be some people will consider JR Hachiko line is named after the famous dog, Hachiko(Hachi) which was waiting for his owner everyday at Shibuya station.
However, it is not the correct. Hachiko is named after due to the line is connecting Hachioji and Takasaki(actually the official terminal station is Kuragano station which is next to Takasaki station. Anyway, Kuragano station is located in Takasaki city in Gunma prefecture). All trains continue from Kuragano to Takasaki and v.v.
Hachiko line is one of the loop lines operated by JR East, running through western Tokyo - Tama district, western Saitama prefecture and southern Gunma prefecture. It is one of the few regional lines of JR East. Fares of regional lines are slightly higher than main lines, such as Chuo main line or Tokaido main line. Hachiko line was the last line to be left non-electrified in Tokyo. Eventually from Hachioji to Komagawa station in Hidaka city, Saitama was electrified in 1996. However, still from Komagawa to Kuragano is left non-electrified and there is no plan to be electrified in future. Therefore there is no through train running between Hachioji and Takasaki. You must change trains at Komagawa station. On the other hand, electric trains from Hachioji continues to Kawagoe station via Kawagoe line.
The frequency is different from electrified part(southern part) and non-electrified part(northern part). Trains are departing each 30 minutes on electrified part but non-electrified part is 1-2 trains per hour but less trains are connecting Komagawa and Takasaki.