Nishikigawa Seiryū Line

The route began as the Japanese National Railways Gannichi Line (岩日線, Gannichi-sen). Its first section, from Kawanishi through the Morigahara signal box to Kawayama, a distance of 27.9 km, opened on 1 November 1960, bringing the seven new stations of Mishō, Minami-Gōchi, Kita-Gōchi, Mukuno, Naguwa, Nekasa and Kawayama into service. On 1 October 1963 the line was extended a further 4.8 km from Kawayama to Nishiki-chō — a passenger-only extension — opening Yanaze and Nishiki-chō stations and bringing the line to its present length of 32.7 km.

Under national-railway operation the line was steadily modernised. Automatic train-stop equipment of the ATS-S type came into use on 1 November 1965, and steam-locomotive operation ended in April 1967. A provisional halt at Yukaba opened on 1 March 1971. Freight service over the Kawanishi–Kawayama section was discontinued on 1 October 1974, leaving the line to carry passengers alone.

The Gannichi Line was always conceived as part of a longer route. A northward extension, the so-called Gan'nichi-hoku Line, was planned to run on from Nishiki-chō to Nichihara in Shimane Prefecture, where it would have met the Yamaguchi Line. Construction of this extension began in 1967, and about half of the roadbed had been built — with tunnels and bridges driven through the mountains north of Nishiki-chō — when the work was abandoned in 1980. The corridor was never opened as a railway, and part of the unbuilt formation was later put to use as a sightseeing course.

Like many lightly used rural lines, the Gannichi Line was caught up in the restructuring of the national railways. On 22 June 1984 it was approved for abolition as a second-batch Specified Local Line, the category of low-traffic routes marked for closure or conversion. Rather than close the line outright, local interests chose to keep it running, and on 14 November 1986 the decision was taken to convert it into a third-sector railway.

When Japanese National Railways was divided and privatised on 1 April 1987, the line passed first to the West Japan Railway Company (JR West), and on the same day the Yukaba provisional halt was upgraded to a full station. The transfer to private operation followed within months: on 25 July 1987 the JR Gannichi Line was abolished and reopened the same day as the Nishikigawa Railway's Nishikigawa Seiryū Line, the new company's sole line.

Under the Nishikigawa Railway the line continued to evolve. A special automatic block system came into use on the Kita-Gōchi–Nishiki-chō section on 16 March 1991, and Shūchi-Kasagami Station opened on 18 March 1993. On 16 March 2013 Mishō Station was renamed Seiryū-Shin-Iwakuni, reflecting its interchange with the nearby Sanyō Shinkansen. The line's scenic setting was made the centrepiece of its identity: on 19 March 2019 Seiryū Mihfrashi Station — a viewing platform between Naguwa and Nekasa, served only by special excursion trains and built to let passengers take in the Nishiki River — was opened.

The line's reliance on the river valley also leaves it exposed to flooding. During the heavy rain disaster of July 2018 the whole line was put out of service from 6 July 2018. Service resumed on the Kita-Gōchi–Nishiki-chō section on 18 July, with replacement buses running between Iwakuni and Kita-Gōchi, and the entire line reopened on 27 August 2018. Today the Nishikigawa Seiryū Line survives as a tourist-oriented local railway, prized chiefly for the river scenery that gives it its name.

• 19601 November: the JNR Gannichi Line opens its first section, Kawanishi–Morigahara signal box–Kawayama (27.9 km), with seven new stations.
• 19631 October: the line is extended 4.8 km from Kawayama to Nishiki-chō (passenger service only), reaching its present 32.7 km.
• 19651 November: automatic train-stop equipment (ATS-S) comes into use.
• 1967April: steam-locomotive operation ends. Construction of the planned Gan'nichi-hoku extension from Nishiki-chō toward Nichihara also begins this year.
• 19711 March: the Yukaba provisional halt opens.
• 19741 October: freight service over the Kawanishi–Kawayama section is discontinued.
• 1980Construction of the Nishiki-chō–Nichihara extension is abandoned with about half of the roadbed completed; the corridor never opens as a railway.
• 198422 June: the Gannichi Line is approved for abolition as a second-batch Specified Local Line.
• 198614 November: the decision is taken to convert the line into a third-sector railway.
• 19871 April: with the breakup and privatisation of JNR, the line passes to JR West; the Yukaba halt is upgraded to a full station.
• 198725 July: the JR Gannichi Line is abolished and reopens the same day as the Nishikigawa Railway's Nishikigawa Seiryū Line, the company's only line.
• 199116 March: a special automatic block system comes into use on the Kita-Gōchi–Nishiki-chō section.
• 199318 March: Shūchi-Kasagami Station opens.
• 201316 March: Mishō Station is renamed Seiryū-Shin-Iwakuni.
• 20186 July: the entire line is suspended by the July 2018 heavy-rain disaster; the Kita-Gōchi–Nishiki-chō section reopens on 18 July with replacement buses on the rest, and the whole line reopens on 27 August.
• 201919 March: Seiryū Mihfrashi Station, a viewing halt between Naguwa and Nekasa served only by special excursion trains, opens facing the Nishiki River.