Sotetsu/JR Direct Line

The Sotetsu/JR Direct Line opened 30 November 2019, linking Nishiya on the Sotetsu Main Line to Hazawa Yokohama-Kokudai via a 2.7-kilometre underground spur. The line gave Sotetsu its first direct route to central Tokyo, with trains reaching Shinjuku from Futakoikawa in around 44 minutes.

Breaking the Yokohama Barrier

For most of its history, Sagami Railway (Sotetsu) was described as a line that stopped at Yokohama. Trains from Ebina and Shōnandai reached Yokohama Station and no further — passengers for central Tokyo had to transfer. That changed on 30 November 2019, when the Sotetsu/JR Direct Line opened: a 2.7-kilometre underground spur connecting Nishiya on the Sotetsu Main Line to the JR Tōkaidō Freight Line near Yokohama-Hazawa, giving Sotetsu its first independent route into Tokyo without passing through Yokohama.

The new spur runs entirely underground through residential Kōhoku Ward. At its far end, trains join the JR Tōkaidō Freight Line and proceed via the Yokosuka Line and Shōnan-Shinjuku Line to Shibuya, Shinjuku and Ikebukuro. A new station, Hazawa Yokohama-Kokudai, was created at the junction and is jointly operated by Sotetsu and JR East; it serves the area around Yokohama National University. The journey from Futakoikawa to Shinjuku takes approximately 44 minutes — door to door from western Yokohama to central Tokyo without a transfer.

The infrastructure was built and is owned by the Japan Railway Construction, Transport and Technology Agency (JRTT), with Sotetsu and JR East operating services under an upper-lower separation arrangement. The line’s design speed is 120 km/h.

First Phase of the Kanagawa East Corridor

This spur was always conceived as the first phase of a broader plan known as the Kanagawa Eastern Corridor Line. The concept appeared in a 1985 government transport-policy council recommendation, which identified a need for a fast link between western Yokohama, the Kanagawa inland area, and central Tokyo. A 2000 follow-up recommendation refined the current alignment, and construction approval came in 2012.

Four years after the 2019 opening, the second phase — the Sotetsu Shin-Yokohama Line and Tokyu Shin-Yokohama Line — opened on 18 March 2023. Extending from Hazawa Yokohama-Kokudai via Shin-Yokohama to Hiyoshi, those lines completed a through-running network spanning seven operators and fourteen routes. What began as 2.7 kilometres of tunnel proved to be the keystone of a much larger structure.

Summary

The Sotetsu/JR Direct Line, opened 30 November 2019, links Nishiya to Hazawa Yokohama-Kokudai through a 2.7-kilometre underground spur, connecting the Sotetsu network to JR’s Shōnan-Shinjuku Line for the first time. As the opening phase of the Kanagawa East Corridor, it laid the groundwork for the seven-operator, fourteen-line network completed when the Shin-Yokohama routes opened in 2023. Stand on the platform at Hazawa Yokohama-Kokudai and watch Sotetsu trains and JR trains share the same track — the scale of what that short spur enables becomes immediately clear.

Related: Sotetsu/Tokyu Shin-Yokohama Line / Shibuya Station Redevelopment

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