Ô’u Honsen (Shinjô – Ômagari – Akita) 　奥羽本線（新庄―大曲―秋田）

Note: The Ô'u Honsen between Ômagari and Akita is also used by 1435 mm gauge Shinkansen trains from Tôkyô via Morioka and the Tazawako-sen. For Shinkansen trains see Tazawako-sen + Akita Shinkansen (Morioka – Akita)

a1  Akayu     a2  Mamurogawa     a3  Yuzawa     a4  Hachirôgata     a5  Takanosu     a6  Ôwani Onsen

A  Zaô (Volcano)     B  Asahidake     C  Gassan (the highest of the 3 Dewa Mountains Hagurosan, Yudonosan, Gassan, significant pilgrimage spots associated with activities and beliefs linked to sacred mountains)    D  Chôkaisan (Volcano)     E  Iwakisan (Volcano)

The Ô'u Honsen was one of the major railway lines to the north, connecting Tôkyô with the plateau of Yamagata and, beyond it, the city of Akita, one of the main Japan Sea ports in northern Japan. From Akita northwards the Ô'u Honsen forms a link with the city and port of Aomori, from where ferries cross the Tsugaru Strait to Hokkaidô. The name "Ô'u　奥羽" refers on the one hand to the Province of Mutsu 陸奥 (basically present-day Aomori Prefecture), on the other hand to the two old provinces surrounding the 3 Dewa Mountains (出羽三山), namely Ugo 羽後 (basically present-day Akita Prefecture) and Uzen 羽前 (basically present-day Yamagata Prefecture).

Since the opening of the high-speed Shinkansen links to the north the Ô'u Honsen has lost much of its significance. Its southern part, the former 1067 mm gauge incline between Fukushima (71 metres above sea level) and Yamagata (136, 5 metres above sea level) via Yonezawa (248, 7 m.a.s.l.), was re-gauged to 1435 mm in 1991 to allow Shinkansen trains from Tôkyô to work through to Yamagata (services began on July 1, 1992). The continuation of 1435 mm gauge Shinkansen services through the Yamagata plateau as far as Shinjô was opened on December 4, 1999. From Shinjô northwards across the border into Akita Prefecture (Yuzawa – Yokote – Ômagari) there are only a few local trains (9 services stopping at all stations) per day, with a few more in the area around Yokote.

Through services to Akita from Tôkyô no longer pass through Yamagata but are also high-speed Shinkansen workings, branching off the Tôhoku Shinkansen main line at Morioka and working over the re-gauged (1067 mm to 1435 mm gauge) local Tazawako-sen to Ômagari and – after reversing – on to Akita. Shinkansen services to Akita began on March 22, 1997. The line between Ômagari and Akita is dual-gauge to enable both standard gauge Shinkansen trains from Tôkyô as well as 1067 mm gauge local trains from Shinjô via Yokote to reach Akita. Between the stops of Jingûji and Mine Yoshikawa just north-west of Ômagari (over a distance of around 12 km) one of the two standard-gauge lines has a third rail for 1067 mm gauge trains; on the rest of the section from Ômagari to Akita one line is 1067 mm gauge, the other line 1435 mm gauge.

The complete section between the Yamagata area and Akita has been electrically worked (AC 20 kV/50 Hz) since 1975. All freight services ceased by 2002.

Coming from the south, the 1067 mm gauge part of the present-day Ô'u Honsen begins at Shinjô (102, 8 metres above sea level). However, there is no more physical connection with the Fukushima to Shinjô section due to the difference of gauge. After Shinjô trains follow the Mamurogawa River into the very remote mountain region of northern Yamagata Prefecture and then cross into Akita Prefecture by means of the summit tunnel beyond Nozoki (271, 3 m.a.s.l.). After the steep descent to Innai (177, 4 m.a.s.l.) the line enters the southern Akita plateau, noted for its diverse vegetable and fruit plantations (grapes, peach, apples etc.). Yokote, which sees extremely heavy snowfall in winter, is well-known for its snow festival in February. Here at Yokote Kitakami-sen trains arrive from Kitakami across the mountains in the east. Continuing through agricultural land the Ô'u Honsen arrives at Ômagari junction (24, 7 m.a.s.l., 98, 4 km from Shinjô), where it is met by the Shinkansen from Morioka and Tôkyô. Continuing down mainly through dense forests the 1067 mm gauge Ô'u Honsen and the 1435 mm gauge Akita Shinkansen arrive side by side at Akita terminal, 298, 7 km from Fukushima, and 51, 7 km from Ômagari.

Since 2017 JR runs occasional special trains to and from Akita Harbour (Akita-kô) to meet cruise ships (7, 1 km up the main line from Akita, and 2, 7 km over the harbour branch).

The Ô'u Honsen, which is frequently hit by heavy rainstorms, landslides and flooding, was completed in its entire length by 1905.

Shinjô is the endstop of Shinkansen trains (here train 322-2007) arriving from Tôkyô via Fukushima and Yamagata, and also of 1435 mm gauge local trains from Fukushima. On the left is 1067 mm gauge train set 701-36 on an Akita - Shinjô working. (2010)

Out of train set 701-36 descending from the summit tunnel and Nozoki towards Shinjô, between Uzen Toyosato and Izumita. (2017)

Train set 701-36 (KUHA 700-36 + KUMOHA 701-36) at Mamurogawa. (2017)

The lonely halt at Nozoki, looking northwards. (2010)

From the rear of a train descending from the summit tunnel to Nozoki. The train has just crossed the border from Akita into Yamagata Prefecture. (2010)

From the rear of a train ascending from Innai towards the summit tunnel. Here the line is double-track. (2010)

Two-car train set 701-36 standing at Innai, at the southern end of the of the South Akita plateau. It will now tackle the ascent to the summit tunnel. (2017)

A view of Innai station. (2017)

Between Mitsuseki and Yokobori, not long before reaching Innai on a train from Akita. (2017)

Running through the orchards in the region of Jûmonji, slightly south of Yokote. Taken from the rear of train set 701-27. (2010)

Waiting at the platform of the Ô'u Honsen at Yokote station. On the left is a train of the Kitakami-sen, formed of diesel cars KIHA 100 no. 6 and no. 4. (2013)

Train set 701-102 (KUMOHA 701-102 + KUHA 700-102) at Gosannen, just north of Yokote. (2017)

Preparing large rotary snowploughs of class ENR-1000 for the winter, at Ômagari. (2013)

Kariwano station, on the section where Shinkansen trains can cross thanks to a third rail in the Ômagari - Akita line. The 1435 mm gauge Akita - Ômagari track is on the left. Waiting at the station is 1067 mm gauge train set 701-38 on a local service to Akita. Note the complex heating equipment for the points. (2017)

An Akita Shinkansen train (class E6 no. 5) crossing a 1067 mm gauge local train near Ôbarino, about 20 km from Akita. (2013)

An Akita Shinkansen train class E6 coming towards a 1067 mm gauge local working near Ôbarino, about 20 km from Akita. (2017)

Train set 701-102 at Wada, about 13 km from Akita. (2013)

Before reaching Akita the train passes the JR maintenance depot in which both 1435 mm trains as well as 1067 mm trains are to be seen. On the right are several 1435 mm gauge sets of class 701-5000, which work local services over the Tazawako-sen between Morioka and Ômagari. Behind them is a class E3 Akita Shinkansen and a 1067 mm gauge diesel train of the Oga-sen. (2013)