Mugi Line

The line was assembled over several decades from pieces of different origin. Its northernmost stretch, between Tokushima and Chūden, began life as part of a coastal connector to Komatsushima harbour: the Awa Steamship Company, which ran ferries between Honshū and Shikoku, opened a railway from Tokushima to Komatsushima in 1913, and from the outset the Railway Agency leased and operated it as the Komatsushima Light Railway. The section onward from Chūden to Hanoura came from a separate private concern, the Anan Railway, which opened its Chūden–Furushō line in 1916. Both undertakings passed into state hands — the Awa Steamship railway was nationalised in 1917, and the Anan Railway in 1936.

Construction of the Mugi Line proper, pushing south beyond the older lines, was a government project. The first segment to carry the Mugi Line name, Hanoura to Kuwano, opened on 27 March 1936, and a few months later the nationalised Anan Railway track was folded into the route. The railhead then advanced down the coast in stages: Kuwano to Awa-Fukui in 1937, Awa-Fukui to Hiwasa in 1939, and Hiwasa to Mugi in 1942, which carried the line some 35 kilometres further south. During the war the line saw tragedy: on 30 July 1945 a train crossing the Naka River bridge was strafed by two American Grumman fighters, killing more than thirty people.

After the war attention turned to extending the line still further south toward Muroto in neighbouring Kōchi Prefecture, where it was meant to meet a planned extension of the Asa Line from Kōchi. The Japan Railway Construction Corporation built the next stage, and on 1 October 1973 the Mugi–Kaifu section opened for passenger traffic, giving the line a length of 79.3 kilometres to Kaifu at the time. Further construction southward continued until work was suspended in 1980, and the line stopped well short of Muroto. The branch arrangements of the older sections were also rationalised over these years — the freight-only Hanoura–Furushō spur closed in 1961, and the short Komatsushima Line linking Chūden to Komatsushima closed in 1985.

With the division and privatisation of the Japanese National Railways on 1 April 1987, the Mugi Line passed to the newly created Shikoku Railway Company (JR Shikoku). The following year construction south of Kaifu was restarted by a private company underwritten by the Tokushima Prefectural Government, and that work eventually opened in 1992 as the Asa Kaigan Railway's Asatō Line; from 26 March 1992 trains ran through between the Mugi Line and the new third-sector line. The line gained its "Awa-Muroto Seaside Line" nickname in 2002, and limited expresses such as the Muroto and Tsurugisan served the corridor in the decades around the turn of the century.

In its most recent reshaping, the line's southern tip was handed over to the Asa Coast Railway. After a period of bus substitution for DMV-related works, JR Shikoku discontinued rail operations between Awa-Kainan and Kaifu on 31 October 2020, and on 1 November 2020 that section was incorporated into the Asa Coast Railway's Asatō Line — the change that fixed the Mugi Line's present terminus at Awa-Kainan and its length at 77.8 kilometres. The Asa Coast Railway went on to launch the world's first regular DMV service from Awa-Kainan in December 2021.

Today the Mugi Line is a rural, locally focused route. Most trains are divided at Mugi, with separate services covering the Tokushima–Mugi, Tokushima–Awa-Kainan and Mugi–Awa-Kainan sections, and driver-only operation is normal on lightly used daytime runs. The line's last regularly scheduled limited express, the Muroto, was discontinued in the March 2025 timetable revision, ending regular premium service on the line; JR Shikoku has meanwhile coordinated with Tokushima Bus so that highway-bus services parallel to the thinly used southern end can be used on JR tickets.

• 191320 April: the Awa Steamship Company opens the Tokushima–Komatsushima line; the Railway Agency leases and runs it as the Komatsushima Light Railway. Its Tokushima–Chūden portion later becomes the northern end of the Mugi Line.
• 191615 December: the private Anan Railway opens the Chūden–Furushō line; Chūden Station opens. This becomes the Chūden–Hanoura portion of the route.
• 19171 September: the Awa Steamship Company's railway is nationalised and continues as the (state) Komatsushima Light Railway.
• 193627 March: the Hanoura–Kuwano segment opens as the first section to carry the Mugi Line name; on 1 July the nationalised Anan Railway track (Chūden–Furushō) is incorporated into the Mugi Line.
• 193727 June: the line is extended from Kuwano to Awa-Fukui.
• 193914 December: the line is extended from Awa-Fukui to Hiwasa.
• 19421 July: the Hiwasa–Mugi segment opens, completing the wartime extension some 35 km south of Kuwano.
• 194530 July: a train crossing the Naka River bridge is strafed by two American Grumman fighters, killing more than thirty people.
• 19611 April: the freight-only Hanoura–Furushō branch closes; the Mugi Line is redefined as Tokushima–Mugi and the Komatsushima Line as Chūden–Komatsushima.
• 19731 October: the Mugi–Kaifu section opens for passenger traffic, built by the Japan Railway Construction Corporation as part of the Asa Line; the line then runs to Kaifu (79.3 km at the time).
• 1980Construction southward beyond Kaifu, intended to reach Muroto and meet the Asa Line from Kōchi, is suspended; the line stops short of Muroto.
• 198514 March: the Komatsushima Line (Chūden–Komatsushima), the surviving stub of the 1913 harbour connector, closes.
• 19871 April: with the division and privatisation of the Japanese National Railways, the Mugi Line passes to the Shikoku Railway Company (JR Shikoku).
• 199226 March: through service begins between the Mugi Line and the new Asa Kaigan Railway Asatō Line, the prefecturally underwritten extension south of Kaifu opened that year.
• 20021 July: the line adopts its official nickname, the 'Awa-Muroto Seaside Line'.
• 202031 October: JR Shikoku discontinues rail operations between Awa-Kainan and Kaifu; on 1 November that section is incorporated into the Asa Coast Railway Asatō Line, fixing the Mugi Line's terminus at Awa-Kainan and its length at 77.8 km.
• 202515 March: the limited express Muroto is discontinued in the timetable revision, ending regularly scheduled premium service on the line.