Kita-Rias Line

The corridor began as two separate, unconnected Japanese National Railways (JNR) projects to serve the isolated fishing communities of the Sanriku coast. JNR opened the Miyako Line from Miyako to Tarō, a distance of 12.8 km, on 27 February 1972, and the Kuji Line from Kuji to Fudai, 26.0 km, on 20 July 1975. The central Tarō–Fudai gap remained under construction, leaving the two ends of the route disconnected for years.

Both of these lightly used lines were slated for closure as JNR's finances deteriorated in the early 1980s. Rather than abandon them, Iwate Prefecture and the municipalities along the coast 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 Miyako–Kuji route as the Kita-Rias Line: the former JNR Miyako and Kuji sections were transferred to Santetsu and the newly built Tarō–Fudai section, 32.2 km long, opened at last, completing the line. The Masaki and Ōmoto tunnels, among the longest on the route, both opened with it that year.

For a quarter of a century the line carried local passengers along a remote and scenic coast. That settled existence was shattered on 11 March 2011, when 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.

The Kita-Rias Line then became one of the most visible symbols of the region's recovery, because Santetsu restored service in stages beginning only days after the disaster. On 16 March 2011, just five days after the earthquake, the Rikuchū-Noda–Kuji section reopened, run as free 'recovery-support' trains; Miyako–Tarō followed on 20 March and Tarō–Omoto on 29 March. The restored trains, running through a devastated coastline, became a powerful emblem of resilience.

Reopening the worst-damaged central stretch took years of reconstruction. On 1 April 2012 the Tanohata–Rikuchū-Noda section returned to service, leaving Shimanokoshi as the only station still closed. Full restoration came on 6 April 2014, when the Omoto–Tanohata section reopened and the Kita-Rias Line — and with it the whole Sanriku Railway network — was once again running end to end.

The line's final transformation came in 2019. The parallel JR East Yamada Line along the coast had also been severed by the tsunami, and rather than restore it itself JR East rebuilt the Kamaishi–Miyako section and handed it to Sanriku Railway. On 23 March 2019 that transfer took effect, linking the Kita-Rias Line at Miyako with the Minami-Rias Line at Kamaishi to form a single continuous Rias Line of 163.0 km and 41 stations, from Sakari in Ōfunato to Kuji. The North Rias name endures as the Miyako–Kuji administrative section of that unified line, and it is the name carried on this map.

• 197227 February: JNR opens the Miyako Line from Miyako to Tarō (12.8 km), the first part of what would become the line.
• 197520 July: JNR opens the Kuji Line from Kuji to Fudai (26.0 km); the central Tarō–Fudai gap is still under construction.
• 1981Iwate Prefecture and coastal municipalities 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 Miyako–Kuji route (71.0 km) as the Kita-Rias Line — the former JNR Miyako and Kuji sections are transferred and the new Tarō–Fudai section (32.2 km) opens, completing the line; the Masaki (6,532 m) and Ōmoto (5,174 m) tunnels open with it.
• 201111 March: the Great East Japan Earthquake and tsunami suspend the entire line; across Santetsu's two lines damage occurs at ~300 locations and about 5.8 km of track is washed away.
• 201116 March: only five days after the disaster, the Rikuchū-Noda–Kuji section reopens, run as free 'recovery-support' trains.
• 201120 March: the Miyako–Tarō section reopens; 29 March: the Tarō–Omoto section reopens, both as free recovery-support trains.
• 20121 April: the Tanohata–Rikuchū-Noda section reopens, leaving Shimanokoshi as the only station still closed.
• 20146 April: the Omoto–Tanohata section reopens, fully restoring the Kita-Rias Line and the whole Sanriku Railway network.
• 201923 March: the JR East Yamada Line section from Kamaishi to Miyako is transferred to Sanriku Railway, joining the Kita-Rias and Minami-Rias lines into a single through Rias Line.
• 2019The unified Rias Line runs 163.0 km from Sakari (Ōfunato) to Kuji with 41 stations; the Kita-Rias Line endures as its Miyako–Kuji administrative section.
• 2019Wikidata records the Kita-Rias Line as a railway line that ended on 23 March 2019, 71 km long, operated by Sanriku Railway — confirming its absorption into the Rias Line.