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Ako Line

赤穂線

The Akō Line (赤穂線, Akō-sen) is a 57.4-kilometre railway line operated by the West Japan Railway Company (JR West), running along the coast of the Seto Inland Sea between Aioi Station in Aioi, Hyōgo Prefecture, and Higashi-Okayama Station in Naka-ku, Okayama, Okayama Prefecture.

Laid to 1,067 mm narrow gauge, single-track and electrified throughout at 1,500 V DC, it serves as a coastal alternative to the inland Sanyō Main Line, which links the same two endpoints by a longer route through the hills. The line passes through Akō, the former castle town of the Akō Domain, known for Chūshingura, the play based on the Akō incident.

OkayamaBizenWake10 km
Route of the Ako Line · Hyogo · Okayama · Boundaries: MLIT / GSI / Japan Post

History

Work on the line began in 1938 but was halted as the Pacific War intensified; it resumed after the war, and the Japanese National Railways (JNR) opened the line in stages over little more than a decade. The first section, between Aioi and Banshū-Akō, opened on 12 December 1951, a distance of 10.5 kilometres; two weeks later, on 26 December 1951, through services began running between Himeji and Banshū-Akō over the new line and the Sanyō Main Line.

Construction then pushed westward along the coast. The line was extended from Banshū-Akō to Hinase on 1 March 1955, adding 11.6 kilometres, and on from Hinase to Inbe on 25 March 1958, a further 12.4 kilometres. The final 22.9-kilometre section, from Inbe through to Higashi-Okayama, opened on 1 September 1962, completing the through route between Aioi and Higashi-Okayama and giving trains a second corridor between the Himeji and Okayama areas.

Electrification followed the construction in two phases. The eastern Aioi–Banshū-Akō section was electrified at 1,500 V DC on 30 March 1961, ahead of the line's full opening. The remaining, longer western portion between Banshū-Akō and Higashi-Okayama was not electrified until 24 August 1969, at which point the entire Akō Line was under wire and through electric operation across its whole length became possible.

Through the 1960s the line continued to fill out: intermediate stations were added, with Sōgo Station opening on 1 April 1962, Tenwa and Nishi-Katakami stations on 1 May 1963, and the Nishihama signal station established on 1 October 1966. Centralised traffic control (CTC) was commissioned on the western part of the line on 29 July 1983, allowing train movements there to be supervised remotely.

With the privatisation and division of the Japanese National Railways on 1 April 1987, the Akō Line passed to the newly formed West Japan Railway Company, which has operated it ever since; Japan Freight Railway (JR Freight) holds running rights for freight service over the line. In the JR West era the eastern end was integrated into the company's Urban Network around the Kansai region, and from 16 March 1996 Special Rapid (shinkaisoku) services were extended onto the Aioi–Banshū-Akō section during the evening rush, later expanded to daytime hours before being scaled back to peak periods.

More recent decades have brought service and systems upgrades. IC card use with ICOCA began on 1 November 2003 and was extended across the whole line by 15 September 2018; one-person (wanman) operation was introduced on the Banshū-Akō–Okayama section from 16 October 2004; and 227-series 500-subseries trains entered regular service between Banshū-Akō and Higashi-Okayama on 12 October 2025.

Stations on this line

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

Timeline
  • 195112 December: the first section, Aioi–Banshū-Akō (10.5 km), opens.
  • 195126 December: through services begin between Himeji and Banshū-Akō via the new line and the Sanyō Main Line.
  • 19551 March: the line is extended from Banshū-Akō to Hinase (11.6 km).
  • 195825 March: the line is extended from Hinase to Inbe (12.4 km).
  • 196130 March: the Aioi–Banshū-Akō section is electrified at 1,500 V DC.
  • 19621 April: Sōgo Station opens.
  • 19621 September: the final Inbe–Higashi-Okayama section (22.9 km) opens, completing the through route between Aioi and Higashi-Okayama.
  • 19631 May: Tenwa and Nishi-Katakami stations open.
  • 19661 October: the Nishihama signal station is established.
  • 196924 August: the Banshū-Akō–Higashi-Okayama section is electrified, completing electrification of the whole line.
  • 198329 July: centralised traffic control (CTC) is commissioned on the western part of the line, as far as Higashi-Okayama.
  • 19871 April: with the privatisation and division of Japanese National Railways, the line passes to JR West (with JR Freight holding running rights).
  • 199616 March: Special Rapid (shinkaisoku) services are extended onto the Aioi–Banshū-Akō section during the evening rush.
  • 20031 November: ICOCA IC card service begins on the line.
  • 200416 October: one-person (wanman) operation begins on the Banshū-Akō–Okayama section.
  • 201815 September: ICOCA support is completed across the entire line.

Sources

Last updated 16 October 2026.

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