Kōnan Line

The line was built by the Kōnan Railway itself, a company founded in 1926. A railway licence for the Watokumura–Onoemura section was granted on 18 February 1926, and after about eighteen months of construction the first segment, between Kōnan-Hirosaki (present-day Hirosaki) and Tsugaru-Onoe, opened on 7 September 1927. The very first train left Tsugaru-Onoe for Kōnan-Hirosaki at 12:05, and the line carried passengers and freight from the outset across the farmland south-east of Hirosaki.

Through the 1930s the railway experimented with mixed traction. Gasoline-railcar operation was authorised in April 1932, and in May that year three small gasoline-car-only halts — Sabunai, Ishigō and Arata — were opened along the route; all three were closed again in February 1943 as wartime conditions tightened. Steam and gasoline working continued until after the Second World War, when the company turned decisively to electric operation.

Electrification came on 1 July 1948, when the whole line was energised at 600 V DC — the first railway electrification in Aomori Prefecture. The route was then completed eastward: on 1 July 1950 the section from Tsugaru-Onoe to Kōnan-Kuroishi (present-day Kuroishi) opened, giving the line its full 16.8-kilometre length from Hirosaki to Kuroishi. The supply voltage was raised in two stages thereafter, to 750 V on 1 April 1954 and to 1,500 V on 1 September 1961, the level still in use today.

From the 1960s and 1970s the line was steadily modernised. Automatic block signalling was introduced section by section between 1970 and 1978, a rapid (express) service began on 1 November 1975, and freight operations were discontinued on 1 July 1984. On 1 April 1986 the terminal stations Kōnan-Hirosaki and Kōnan-Kuroishi were renamed simply Hirosaki and Kuroishi, and one-man (driver-only) operation began on 1 April 1993. New intermediate stations were added over the years — among them Undōkōenmae in 1977, Hakunōkōkōmae in 1980 and Onoekōkōmae in 1999 — many of them serving schools along the line.

The line has seen two notable accidents. On 25 August 1997 two trains collided head-on within Tachita Station, injuring thirty-two people. On 12 June 2007 a Kuroishi-to-Hirosaki train derailed at Hiraka Station without injuries; a provisional timetable ran until normal services resumed on 1 August, but the rapid service that had operated since 1975 was suspended in the aftermath and, in effect, abolished. An automatic train stop (ATS) system had been brought into use in November 1999.

In recent years the Kōnan Line has become as much a local attraction as a means of transport. Tamboāto ("rice-paddy art") Station, serving the famous paddy-field artwork at Inakadate, opened on 27 July 2013 and is used only in the growing season. Four-car operation was discontinued in 2019, and from 2021 the line's surrounding municipalities drew up a support plan to keep it running; station numbering, with the line code "KK", was announced on 12 April 2021. The line is also known for its winter snow-clearing work, retaining a Russell snowplough car for the heavy snows of the Tsugaru plain.

A rail defect found between Kuroishi and Sakaimatsu on 25 September 2023 suspended the whole line; replacement buses ran from 2 October, the Hirosaki–Tamboāto section reopened on 26 October, and full operation resumed on 7 November 2023, though a reduced timetable was kept until March 2024 while substation equipment was renewed. Today the Kōnan Line runs all-stations services between Hirosaki and Kuroishi with two-car, one-man trains, using former Tokyu 7000 series cars and carrying the commuters, schoolchildren and visitors of Hirosaki's apple-and-rice country.

• 192618 February: a railway licence is granted to the Kōnan Railway for the Watokumura–Onoemura section; the company is founded this year.
• 19277 September: the Kōnan Railway opens its first segment, Kōnan-Hirosaki (now Hirosaki)–Tsugaru-Onoe; the first train leaves Tsugaru-Onoe at 12:05.
• 1932April: gasoline-railcar operation is authorised; in May, three gasoline-car-only halts (Sabunai, Ishigō, Arata) open along the line.
• 194325 February: the three gasoline-car halts (Sabunai, Ishigō, Arata) are closed.
• 19481 July: the whole line is electrified at 600 V DC — the first railway electrification in Aomori Prefecture.
• 19501 July: the Tsugaru-Onoe–Kōnan-Kuroishi (now Kuroishi) section opens, completing the line at 16.8 km from Hirosaki to Kuroishi.
• 19541 April: the line's supply voltage is raised from 600 V to 750 V.
• 19611 September: the supply voltage is raised to 1,500 V, the level still in use today.
• 19751 November: a rapid (express) service begins operating on the line.
• 19841 July: freight operations on the line are discontinued.
• 19861 April: Kōnan-Hirosaki Station is renamed Hirosaki and Kōnan-Kuroishi Station is renamed Kuroishi.
• 19931 April: one-man (driver-only) operation begins.
• 199725 August: two trains collide head-on within Tachita Station, injuring thirty-two people.
• 19991 November: an automatic train stop (ATS) system comes into use (Onoekōkōmae Station had opened on 1 April).
• 200712 June: a Kuroishi-to-Hirosaki train derails at Hiraka Station without injuries; normal services resume on 1 August, but the rapid service is suspended and in effect abolished.
• 201327 July: Tamboāto ('rice-paddy art') Station opens, serving the paddy-field artwork at Inakadate; it is used only in the growing season.
• 202112 April: station numbering, with the line code 'KK', is announced; from January the surrounding municipalities had drawn up a plan to keep the line running.
• 202325 September: a rail defect between Kuroishi and Sakaimatsu suspends the whole line; replacement buses run from 2 October and full service resumes on 7 November, with a reduced timetable kept until March 2024 for substation renewal.