Minami-Rias Line

Japanese National Railways (JNR) opened the Sakari Line from Sakari to Ryori, a distance of 9.1 km, on 1 March 1970, and extended it from Ryori to Yoshihama, a further 12.5 km, on 1 July 1973. The remaining stretch on to Kamaishi was still under construction, leaving the line short of its intended northern terminus for years.

The Sakari Line was later slated for closure. Rather than abandon it, backers led by Iwate Prefecture established the Sanriku Railway in 1981 as the country's first 'third-sector' (joint public-private) railway company. On 1 April 1984 the company opened the whole Sakari–Kamaishi route as the Minami-Rias Line: the former JNR Sakari Line section was transferred to Santetsu and the newly built Yoshihama–Kamaishi section, 15.0 km long, opened at last, completing the line. The same day, the company also opened its northern Kita-Rias Line, and the two together formed the original Sanriku Railway network.

For a quarter of a century the line carried local passengers along the coast. On 11 March 2011 the Great East Japan Earthquake and the tsunami it generated struck the Sanriku coast. The entire line was suspended; across Sanriku Railway's two lines damage was recorded at roughly 300 locations, including station buildings and bridges, and the tsunami washed away some 5.8 km of track.

Service on the South Rias Line returned in two stages. On 3 April 2013 the Sakari–Yoshihama section, 21.6 km, reopened, restoring trains over the southern part of the line. Full restoration came on 5 April 2014, when the Yoshihama–Kamaishi section, 15.0 km, returned to service and the Minami-Rias Line was once again running end to end — part of the wider restoration of the whole Sanriku Railway network completed that April.

The Kamaishi–Miyako section between Santetsu's two lines belonged to the JR East Yamada Line. It had opened in stages in the 1930s as part of the Railway Ministry's Yamada Line, and it too had been severed by the tsunami. JR East carried out the restoration work on that section and then handed it to Sanriku Railway. On 23 March 2019 that transfer took effect, linking the Minami-Rias Line at Kamaishi with the Kita-Rias Line at Miyako to form a single continuous Rias Line of 163.0 km and 41 stations, running from Sakari in Ōfunato to Kuji.

The South Rias name endures as the Sakari–Kamaishi administrative section of that unified line, 36.6 km of the 163.0-kilometre whole, and it is the name carried on this map.

10 stations tracked on the map, listed alphabetically. Select any to read its page.

• Heita平田
• Horei甫嶺
• Kamaishi釜石
• Koishihama恋し浜
• Rikuzen-Akasaki陸前赤崎
• Ryori綾里
• Sakari盛
• Sanriku三陸
• Toni唐丹
• Yoshihama (Iwate)吉浜

• 19701 March: JNR opens the Sakari Line from Sakari to Ryori (9.1 km), the first part of what becomes the Minami-Rias Line.
• 19731 July: the JNR Sakari Line is extended from Ryori to Yoshihama (12.5 km); the section on to Kamaishi is still under construction.
• 1981Backers led by Iwate Prefecture establish the Sanriku Railway, Japan's first third-sector railway company, to take over the JNR lines slated for closure.
• 19841 April: Sanriku Railway opens the whole Sakari–Kamaishi route (36.6 km) as the Minami-Rias Line — the former JNR Sakari Line is transferred and the new Yoshihama–Kamaishi section (15.0 km) opens, completing the line; the Kita-Rias Line opens the same day.
• 201111 March: the Great East Japan Earthquake and tsunami suspend the entire line; across Santetsu's two lines damage occurs at about 300 locations and some 5.8 km of track is washed away.
• 20133 April: the Sakari–Yoshihama section (21.6 km) reopens, restoring trains over the southern part of the line.
• 20145 April: the Yoshihama–Kamaishi section (15.0 km) reopens, fully restoring the Minami-Rias Line as part of the wider restoration of the whole Sanriku Railway network completed that April.
• 201923 March: the rebuilt JR East Yamada Line section from Kamaishi to Miyako is reopened and transferred to Sanriku Railway, joining the Minami-Rias Line at Kamaishi with the Kita-Rias Line at Miyako to form a single continuous Rias Line.
• 2019The unified Rias Line runs 163.0 km from Sakari (Ōfunato) to Kuji with 41 stations; the Minami-Rias Line endures as its Sakari–Kamaishi administrative section (36.6 km).
• 201923 March: Sanriku Railway adopts 'Rias Line' as the passenger-information name for the whole Sakari–Kuji route, including the 36.6 km Minami-Rias Line.