Takaoka Kidō Line

The tram half of the present network was not the older part. The Shinminatokō stretch toward Koshinokata had been built from 1930 by the Etchū Railway (越中鉄道) — later the Imizu Line of the Toyama Chihō Railway (Chitetsu) — but the Takaoka Kidō Line itself dates only from after the Second World War. On 10 April 1948 the Toyama Chihō Railway opened a 7.3-kilometre line from Chitetsu-Takaoka (the present Takaoka Station stop) to Fushikikō; at that time it was known as the Fushiki Line (伏木線), or Kōfuku Line. No wholly new street-tramway was built anywhere in Japan for decades afterward — not until the Utsunomiya–Haga line broke ground in 2018 — so the 1948 project came to be called "Japan's last city tramway plan."

The route took its modern shape over the following years. On 1 April 1951 a 3.6-kilometre section from Yonejimaguchi to Shinminato (the present Rokudōji) opened, the Hirokōji–Yonejimaguchi stretch was double-tracked, and through running began via the Imizu Line all the way to Nishichō on the Toyama city tram network. In 1959 the Takaoka tram lines were transferred from the Toyama Chihō Railway to the Kaetsunō Railway (加越能鉄道, founded 1950) as part of a drive to unify transport within Takaoka; through services continued, although the run into central Toyama was discontinued in 1961.

In 1966 the building of the new port of Toyama (Toyama-Shinkō) severed the Imizu Line, and the surviving Shinminato–Koshinokata portion on the Takaoka side was likewise handed to the Kaetsunō Railway, becoming the Shinminatokō Line. With the through route to Toyama gone and motorisation taking hold, ridership began to fall. In 1971, at the request of Takaoka City, the 2.9-kilometre Yonejimaguchi–Fushikikō section — the old Fushiki Line — was abolished, leaving the line in essentially its present form.

The Man'yōsen name comes from this era. In 1980 the Kaetsunō Railway adopted "Man'yōsen" as the joint nickname for the Takaoka Kidō and Shinminatokō lines, honouring the eighth-century poet Ōtomo no Yakamochi, who served as provincial governor at Fushiki in old Etchū and compiled much of the Man'yōshū anthology. Even under the new branding the deficits persisted, and in 2001 the Kaetsunō Railway announced that it intended to abolish both lines and replace them with buses.

Rather than lose the tramway, Takaoka City and the former city of Shinminato led the creation of a third-sector company, Man'yōsen Co., Ltd., established on 5 April 2001. The transfer from the Kaetsunō Railway was approved on 14 February 2002, and the new company began operating both lines as the Man'yōsen on 1 April 2002 — the first time in Japan that a third-sector company had been set up specifically to run a street tramway.

Under the new operator the line was modernised as light rail. From 2004 Man'yōsen introduced the MLRV1000 "Aitram," a low-floor articulated tram, alongside the inherited De 7070 cars; one Aitram set has run since 2012 as the "Doraemon Tram," a nod to the manga's creator who came from the area. Today the Takaoka Kidō Line carries frequent through services with the Shinminatokō Line every fifteen minutes between Takaoka Station and Koshinokata, where a prefectural ferry connects across the mouth of the new port, and renewal of the Aitram fleet with new cars has been signalled from the 2027 fiscal year.

• 194810 April: the Toyama Chihō Railway opens the 7.3 km Chitetsu-Takaoka–Fushikikō line, the origin of the present Takaoka Kidō Line, then known as the Fushiki Line.
• 19511 April: the Yonejimaguchi–Shinminato (present Rokudōji) section, 3.6 km, opens; Hirokōji–Yonejimaguchi is double-tracked; through running to Nishichō on the Toyama city tramway begins via the Imizu Line.
• 19591 April: the Takaoka tram lines are transferred from the Toyama Chihō Railway to the Kaetsunō Railway (founded 1950) to unify transport within Takaoka.
• 196118 July: through running between Shin-Takaoka and Nishichō on the Toyama city tram network is discontinued.
• 19665 April: with the construction of the new port of Toyama severing the Imizu Line, the Shinminato–Koshinokata portion is also transferred to the Kaetsunō Railway and becomes the Shinminatokō Line.
• 19711 September: at Takaoka City's request the 2.9 km Yonejimaguchi–Fushikikō section — the old Fushiki Line — is abolished, leaving the line in essentially its present form.
• 19806 December: the Kaetsunō Railway adopts 'Man'yōsen' as the joint nickname for the Takaoka Kidō and Shinminatokō lines, honouring the poet Ōtomo no Yakamochi.
• 2001The Kaetsunō Railway announces it intends to abolish both lines and replace them with buses; on 5 April the third-sector Man'yōsen Co., Ltd. is established to keep them running.
• 200214 February: the transfer from the Kaetsunō Railway is approved; on 1 April the Man'yōsen company begins operating both lines — the first third-sector company in Japan formed specifically to run a street tramway.
• 200421 January: Man'yōsen introduces the low-floor articulated MLRV1000 'Aitram' tram alongside the inherited De 7070 cars.
• 2012One MLRV1000 'Aitram' set begins running as the 'Doraemon Tram,' a nod to the manga's creator from the area.
• 201429 March: the Takaoka-eki-mae stop is renamed Takaoka-eki and the line is extended 0.1 km when the stop is relocated to the rebuilt station.