Tasaki Line

The line is short but functionally important: it carries the western end of the Kumamoto tram network and provides the connection to Kumamoto Station, the city's main railway gateway on JR Kyūshū's Kagoshima Main Line, Hōhi Main Line, Misumi Line and the Kyushu Shinkansen. Its three stops, numbered from the western terminus inward, are Tasaki-bashi (no. 1), Nihongiguchi (no. 2) and Kumamoto-Eki-mae (no. 3), the last lying at the 0.5-kilometre mark beside Kumamoto Station itself.

The Tasaki Line opened comparatively late in the history of Japan's municipal tramways. On 24 December 1959 the route was brought into service, extending the Kumamoto network westward to Tasaki-bashi and giving the system a direct link to the area around Kumamoto Station. From the outset the line was a standard-gauge, 600 V DC street tramway, sharing the technical standards of the rest of the municipal system.

For much of its life the line saw little structural change, but in the twenty-first century its track layout was rebuilt. On 26 April 2010 the entire line was converted to a "side reservation" configuration, in which the tram tracks were shifted to one side of the roadway so that the running way, the carriageway for road traffic and the footway sat side by side rather than the tracks running down the centre of the street. The arrangement is visible in the stretch leading from in front of Kumamoto Station.

Because Kumamoto Station was being comprehensively redeveloped, the city for a time pursued a plan to run the tramway directly into the station building. From 2006, in step with the project to grade-separate the Kagoshima and Hōhi main lines and to remodel the east-side station plaza, Kumamoto City proposed bringing the tram into the new JR Kumamoto Station building to improve transfers, and reached agreement with the prefecture and other bodies that year. In September 2013 it published a layout plan for the east plaza under which the tram would branch from the existing route, cross the plaza, enter the ground floor of the new station building, and reverse out by a switchback before returning to the main line, with the trackway envisaged as a pedestrian-friendly transit mall.

The station-entry plan was ultimately dropped. Concerns about the safety of pedestrians and cyclists, and about restricting free movement across the station plaza, could not be resolved, and in February 2015 the Mayor of Kumamoto, Kazufumi Ōnishi, told a plenary session of the Kumamoto City Assembly that the city would abandon the idea of taking the tram into the station building and would revise the plaza plan instead, looking thereafter to improve transfers between the tram and buses and taxis.

A more recent disruption came in the summer of 2024. On 26 July 2024 a tram derailed near a set of points while running on the section between Tasaki-bashi and Nihongiguchi, and the stretch between Kumamoto-Eki-mae and Tasaki-bashi was suspended until 28 July, when through service was restored. Today the Tasaki Line continues to form the short western arm of the Kumamoto City Tram, served by the network's A route running through between Tasaki-bashi and Kengun-machi at intervals of about four to seven minutes, and remains the tramway's link to Kumamoto Station.

• 195924 December: the Tasaki Line opens, extending the Kumamoto City Tram westward to Tasaki-bashi.
• 201026 April: the entire line is converted to a side-reservation configuration, with the tracks shifted to one side of the roadway.
• 2013September: the city publishes a plan for the east station plaza under which the tram would enter the new JR Kumamoto Station building and reverse out by a switchback.
• 2015February: Mayor Kazufumi Ōnishi tells the Kumamoto City Assembly that the city will abandon the plan to run the tram into the JR Kumamoto Station building and revise the plaza plan.
• 202426 July: a tram derails near a set of points on the Tasaki-bashi–Nihongiguchi section; service between Kumamoto-Eki-mae and Tasaki-bashi is suspended.
• 202428 July: the suspended section between Kumamoto-Eki-mae and Tasaki-bashi reopens.