Tsuyama Line

Unlike most of Japan's trunk routes, the Tsuyama Line did not begin as a state project. It was built by the Chūgoku Railway (中国鉄道), a private company established on 30 April 1896 under the Private Railway Act. The company's ambition was a main line reaching far inland — from Okayama through Tsuyama and Katsuyama on to Neu and Yonago — but in the event only the Okayama–Tsuyama section was completed. The remaining licences lapsed, and those routes were instead built later by the state as the Kishin Line and the Hakubi Line.

The Chūgoku Railway opened its main line on 21 December 1898, running from Okayama-shi Station to Tsuyama Station over a distance of 34 miles 76 chains, roughly 56.25 km. At first the line did not reach the government's Okayama Station; the gap was closed on 15 November 1904, when the Okayama–Okayama-shi section opened and Chūgoku Railway trains began running into the national railway's Okayama Station, giving the line its present southern terminus.

The line's northern end was reshaped by the growth of the inland network. On 1 August 1923 the original Tsuyama Station was renamed Tsuyama-guchi, and from 1924 the short Tsuyama-guchi–Tsuyama section was folded into the Sakubi Line (the forerunner of today's Kishin Line); the present Tsuyama Station thus became the line's terminus. Through the 1900s to 1930s a string of intermediate stations and halts was added along the route, and in 1930 the line's distances were restated from miles into kilometres.

The Chūgoku Railway remained in private hands for nearly half a century. On 1 June 1944, in the midst of the Pacific War, the company's railway division was nationalised and the route became the Tsuyama Line of Japanese Government Railways, later Japanese National Railways (JNR). Under JNR the line was modernised steadily: its first superior service, the semi-express "Hiruzen," began running in December 1960, joined by the semi-express "Sakyū" in 1962, and centralised traffic control was introduced over the whole line on 31 August 1982.

With the privatisation and break-up of JNR on 1 April 1987, the Tsuyama Line passed to the newly formed West Japan Railway Company, and freight operations on the line ended. JR West pursued further modernisation: one-man operation began on 1 June 1990, a line-wide speed-up programme was completed on 1 December 1996, and on 29 November 1997 the express "Sakyū" was withdrawn in favour of a new express "Tsuyama" and the rapid "Kotobuki."

In the 21st century the line has weathered repeated natural disruptions and continued to modernise. Rockfall-triggered derailments closed the Tamagashi–Makiyama section in February 2005 and again in November 2006, each followed by reopening after countermeasures, and heavy rain shut the whole line for several weeks in July 2018. The express "Tsuyama" was discontinued in 2009, leaving the "Kotobuki" as the line's fast service. IC-card ticketing (ICOCA) reached the line in 2007 and was extended through to Tsuyama in 2024, while tourist trains — the "Nostalgie" from 2016 and the "SAKU-bi SAKU-ra" from 2022 — have been introduced to draw visitors to the inland corridor.

• 189630 April: the Chūgoku Railway, a private company, is established under the Private Railway Act.
• 189821 December: the Chūgoku Railway opens its main line from Okayama-shi to Tsuyama, 34 miles 76 chains (≈56.25 km).
• 190014 April: Takebe Station opens.
• 190415 November: the Okayama–Okayama-shi section opens and Chūgoku Railway trains begin running into the national railway's Okayama Station, the line's present southern terminus.
• 19231 August: the original Tsuyama Station is renamed Tsuyama-guchi.
• 19241 May: the Tsuyama-guchi–Tsuyama section is incorporated into the Sakubi Line (later the Kishin Line); the present Tsuyama Station becomes the line's terminus.
• 19301 April: the line's distances are restated from miles into kilometres.
• 19441 June: the Chūgoku Railway's railway division is nationalised and the route becomes the Tsuyama Line of Japanese Government Railways.
• 19561 October: Obara Station opens.
• 196020 December: the semi-express "Hiruzen," the line's first superior service, begins operation.
• 19621 September: the semi-express "Sakyū" begins running (later upgraded to express in 1966).
• 198231 August: centralised traffic control (CTC) is introduced over the whole line.
• 19871 April: with the privatisation of JNR, the line passes to West Japan Railway Company (JR West); freight service ends.
• 19901 June: one-man operation begins on the line.
• 19961 December: a line-wide speed-up programme is completed.
• 199729 November: the express "Sakyū" is withdrawn; the express "Tsuyama" and the rapid "Kotobuki" begin service.
• 200913 March: the express "Tsuyama" is discontinued, leaving the rapid "Kotobuki" as the line's fast service.
• 20186 July: the whole line is closed by heavy rain; partial service resumes 17 July and full service on 5 August.
• 202421 September: ICOCA IC-card service is extended through to Tsuyama Station.