Green Line (Yokohama) (4号線): History & Facts

History

The line is the first completed piece of a much larger scheme, the Yokohama Circular Railway (横浜環状鉄道), conceived to link the city's suburban centres in a ring. Its roots reach back to the 1960s, when it was first envisaged alongside the Kōhoku New Town; on 11 July 1985 the Transport Policy Council's Report No. 7 recommended a Yokohama Line 4 running from Hiyoshi via Takatachō and the Kōhoku New Town toward the Yokohama Line. The route was intended to link two rail hubs — Hiyoshi, a Tōkyū interchange, and Nakayama on JR's Yokohama Line — by way of the New Town districts in between.

Formal authorisation followed in the late 1990s. The Transportation Bureau applied for a Type 1 railway business licence for the Hiyoshi–Nakayama Line 4 on 31 March 1997, and the licence was granted on 23 May 1997. A groundbreaking ceremony for Line 4 was held on 30 January 2001 at Center Minami Station, an existing Blue Line station that was to become an interchange with the new line.

The line's identity was settled while it was still under construction. On 15 June 2006 the Transportation Bureau decided to call Line 4 the "Green Line", the same day it chose "Blue Line" as the combined name for its existing Lines 1 and 3.

The Green Line opened on 30 March 2008, running the full 13.0 km between Nakayama and Hiyoshi with ten stations from the outset. It gave the Kōhoku New Town a cross-town link it had previously lacked. At Hiyoshi the line connects with the Tōkyū Tōyoko and Meguro lines, at Nakayama with the JR Yokohama Line, and at Center Minami and Center Kita with the Blue Line. Although most of the route is in tunnel, about 2.4 km in all runs in the open: a 1,121 m viaduct between Center Kita and Center Minami, and sections near Kawawachō and Tsuzuki-Fureai-no-Oka stations.

Services have been worked from the opening by the Transportation Bureau's purpose-built 10000 series, a linear-motor electric multiple unit. Sixty cars — fifteen four-car sets — were delivered for the start of operations in 2008, and a further eight cars (two four-car sets) were added in 2014 as ridership grew. To raise capacity further, the bureau began running six-car trains on 24 September 2022, with a programme to lengthen ten of the sets from four to six cars in stages.

The Green Line as built is only the beginning of the Yokohama Circular Railway plan, and extensions are planned at both ends. From Hiyoshi the line is envisaged to run on toward Tsurumi, and from Nakayama it would run via Futamatagawa, Tsurugamine, Higashi-Totsuka, Kami-Ōoka and Negishi, potentially reaching Motomachi-Chūkagai on the Minatomirai Line. The city classes these extensions as a long-term undertaking rather than an imminent project, so for now the Green Line remains the single Nakayama–Hiyoshi segment opened in 2008.

Stations on this line

10 stations tracked on the map, listed alphabetically. Select any to read its page.

Timeline

198511 July: the Transport Policy Council's Report No. 7 recommends a Yokohama Line 4 from Hiyoshi via Takatachō and the Kōhoku New Town toward the Yokohama Line.
199731 March: the Transportation Bureau applies for a Type 1 railway business licence for the Hiyoshi–Nakayama Line 4; the licence is granted on 23 May.
200130 January: a groundbreaking ceremony for Line 4 is held at Center Minami Station on the Blue Line; construction begins.
200615 June: the Transportation Bureau decides on the name 'Green Line' for Line 4 (deciding 'Blue Line' for Lines 1 and 3 the same day).
200830 March: the Green Line opens between Nakayama and Hiyoshi, 13.0 km with ten stations.
2008Revenue services start with the purpose-built 10000 series linear-motor EMU: sixty cars (fifteen four-car sets) delivered for the opening.
2014A further eight cars (two four-car sets) of the 10000 series are added as ridership grows.
202224 September: six-car operation begins, under a programme to lengthen ten of the sets from four to six cars.

Sources

Last updated 16 October 2026.