JR Tokoku Honsen

From Wikipedia:

The Tōhoku Main Line (東北本線 Tōhoku-honsen?) is a 575.7 km long railway line in Japan operated by the East Japan Railway Company (JR East). Although officially the line starts from Tokyo Station in Chiyoda, Tokyo, most of the long-distance trains actually begin at Ueno Station in Taitō, Tokyo, and pass through such cities as Saitama, Utsunomiya, Fukushima, and Sendai, before reaching the end of the line in Morioka. The Tōhoku Main Line runs mostly parallel to the Tōhoku Shinkansen.

The 159.9 km long portion of the line between Ueno Station and Kuroiso Station in Nasushiobara, Tochigi is often referred to as the (JR) Utsunomiya Line. A portion of the Tōhoku Main Line is also shared with the Keihin-Tōhoku Line (29.6 km between Tokyo Station and Ōmiya Station in Ōmiya-ku, Saitama) and the Saikyō Line (18.0 km between Akabane Station in the Kita ward of Tokyo and Ōmiya Station).

It says it is often referred to as the Utsunoiya Line, but it is officially referred to that on all the signs and platforms in Ueno.