Kitto Line

The line began as the Miyazaki Line (宮崎線), a state railway built inland from Yoshimatsu, which was then a station on the Kagoshima Main Line. The first section, from Yoshimatsu to Kobayashi-machi (today's Kobayashi), opened on 1 October 1912, with stations at Kyōmachi, Kakutō, Iino and Kobayashi-machi. The route was pushed eastward the following year: Kobayashi-machi to Tanigashira opened on 11 May 1913, and Tanigashira to Miyakonojō on 8 October 1913, completing what is now the whole Kitto Line.

Construction continued beyond Miyakonojō, and on 25 October 1916 the Miyazaki Line was opened through to Miyazaki, giving the interior of southern Miyazaki its first rail link to the regional network. The line was renamed the Miyazaki Main Line (宮崎本線) on 21 September 1917. As the railway was extended northward and joined the Hōshū Main Line, a continuous route from Kokura down to Miyazaki took shape; when that through connection was completed on 15 December 1923 the whole corridor was redesignated the Nippō Main Line. For these years the present Kitto Line, by way of Yoshimatsu, formed part of the principal trunk route into Miyazaki.

That trunk status ended when a more direct coastal route was built. On 6 December 1932 the Miyakonojō–Hayato section opened, and the Nippō Main Line was rerouted along the coast through Hayato. The older inland alignment between Miyakonojō and Yoshimatsu was thereby separated from the main line and given its own name, the Kitto Line — the name it has carried ever since. The line had meanwhile been gaining intermediate stations, with Nishi-Kobayashi added in 1929 and further stops opened in the post-war years.

Under Japanese National Railways the Kitto Line, although a quiet local route through the mountains, served as part of cross-Kyūshū express itineraries. The semi-express (later express) "Ebino" began running between Kumamoto and Miyazaki on 1 May 1959, and the limited express "Ōyodo" linked Hakata and Miyazaki over the line from 1974. On 21 February 1968 the Ebino earthquake damaged track and bridges on the line, which was restored by the 29th. Steam traction ended on 27 April 1974 — the final steam-hauled train was worked by a Class D51 locomotive — after which diesel locomotives took over. Unusually for a railway through such hilly country, the line has not a single tunnel along its length.

When JNR was divided and privatised on 1 April 1987 the line passed to the newly formed Kyushu Railway Company (JR Kyushu), and freight operations over it were abolished. As an inland line with persistently thin traffic it had long carried a transport density typical of the "specified local lines" earmarked for closure during the JNR reforms, but it escaped that fate under an exemption for lines with long average journeys. Cost-cutting followed under JR Kyushu: one-man operation was introduced on 1 October 1993, the limited express "Ōyodo" had already ended in 1980, the express "Ebino" was discontinued in 2000, and from 26 March 2016 conductors were withdrawn so that all trains ran one-man.

Today the Kitto Line is a rural local line with no premium services, all of its trains being one-man local trains running the full length of the route, with daytime gaps that can exceed several hours; some trains run through onto the Hisatsu Line to and from Hayato, and a few continue over the Nippō Main Line to Minami-Miyazaki or Miyazaki. Passenger numbers have continued to slide, the transport density falling to under 400 per day by the 2020s. The line and its operators have promoted it through tie-ins playing on the homophone of its name — most visibly a "Kitto, negai kanau" wrapped train created with the Nestlé chocolate brand KitKat in 2018–2019. In March 2024 a KiHa 40 railcar was repainted in the old JNR livery to mark the 110th anniversary of the line's opening alongside other regional milestones.

• 19121 October: the Miyazaki Line opens its first section, Yoshimatsu–Kobayashi-machi (now Kobayashi), branching from Yoshimatsu, then a Kagoshima Main Line station.
• 191311 May: Kobayashi-machi–Tanigashira opens. 8 October: Tanigashira–Miyakonojō opens, completing what is now the entire Kitto Line.
• 191625 October: the Miyazaki Line is opened through to Miyazaki.
• 191721 September: the Miyazaki Line is renamed the Miyazaki Main Line.
• 192315 December: with the Kokura–Yoshimatsu route fully connected, the corridor is redesignated the Nippō Main Line; the present Kitto Line forms part of the trunk into Miyazaki.
• 19291 February: Nishi-Kobayashi Station opens.
• 19326 December: the Miyakonojō–Hayato section opens and the Nippō Main Line is rerouted via the coast; the inland Miyakonojō–Yoshimatsu line is separated as the Kitto Line.
• 19591 May: the semi-express (later express) 'Ebino' begins running between Kumamoto and Miyazaki over the line.
• 196821 February: the Ebino earthquake damages track and bridges on the line; it is restored on the 29th.
• 197425 April: the limited express 'Ōyodo' (Hakata–Miyazaki) begins running over the line. 27 April: steam traction ends, the last steam train worked by a Class D51, replaced by diesel locomotives.
• 19801 October: the limited express 'Ōyodo' is discontinued.
• 19871 April: on the division and privatisation of JNR the line passes to the Kyushu Railway Company (JR Kyushu); freight operations over it are abolished.
• 19931 October: one-man operation is introduced on the line.
• 200011 March: the express 'Ebino' is discontinued, ending premium services on the line.
• 201626 March: conductors are withdrawn and all trains become one-man operated.
• 202418 March: a KiHa 40 railcar is repainted in the old JNR livery to mark the line's 110th anniversary (with the Hisatsu Line's 120th and the Ibusuki-Makurazaki Line's 60th).