The is a commuter line operated by Tokyu Corporation connecting Hiyoshi Station on the Tà Âkyà « Tà Âyoko and Meguro lines to Shin-Yokohama Station on the Sà Âtetsu Shin-Yokohama Line. Tà Âkyà « has put its company name as a formal part of the line name, which is a second for Tà Âkyà «, following the Tà Âkyà « Tamagawa Line.
It is a part of the Eastern Kanagawa Rail Link strategic plan for improving the rail network connectivity of Kanagawa Prefecture. The railway line's infrastructure is maintained by the Japan Railway Construction, Transport and Technology Agency (JRTT). Tà Âkyà « collects the operation revenue and pays JRTT for using the rail infrastructures, then JRTT use this payment to maintain the infrastructures and reimburse the loan for the construction of this line.
The Tà Âkyà « Shin-Yokohama Line opened on 18 March 2023.
The line runs between Shin-Yokohama and Hiyoshi, with one intermediate station at , adjacent to on the Tà Âkyà « Tà Âyoko Line.
Sà Âtetsu Shin-Yokohama Line trains run through service with Tà Âkyà «, Tokyo Metro, and Toei Subway Lines via Shin-Yokohama.
Shin-Yokohama Station is jointly operated by Tà Âkyà « and Sà Âtetsu. This is the first case for both operators to have a station with direct connections to the Shinkansen.
Beyond Hiyoshi, trains head towards Shibuya via the Tà Âkyà « Tà Âyoko Line or Meguro via the Tà Âkyà « Meguro Line.
In 2016, Toei announced that thirteen of its 6300 series trainsets (1st and 2nd batch) would be replaced, and in 2019 nine new trainsets compatible with the Sà Âtetsu Line would begin service, with more trainsets to be produced through 2021. In 2018, Toei ramped up its plans and announced that 13 new trainsets with the same designation numbers as the 13 that are replaced would be introduced to service. These new models are formed as 8-car sets made by Kinki Sharyo and classified as 6500 series. The first of these sets entered service on 14 May 2022. The 3rd batch of 6300 series trainsets continued their service on the Mita Line upon being upgraded to enable compatibility with the Sà Âtetsu Line, by introducing digitized communications equipment and the ATS-P system. With Mita Line trainsets extending to 8 cars, Sà Âtetsu underwent preparations to enable compatibility with 8-car trains. Additionally, Sà Âtetsu has also introduced its 20000 series developed for use on Tà Âkyà « through services; the type first entered service in February 2018.
In mid-2022 it was announced that through service trains to the Tà Âkyà « Tà Âyoko Line could continue along the Tokyo Metro Fukutoshin Line to Wakà Âshi and further on the Tà Âbu Tà Âjà  Line. However, trains would not be allowed to run through on the Seibu Yà «rakuchà  and Ikebukuro Lines. Passengers must transfer at Kotake-Mukaihara Station. Beyond Shin-Yokohama and Nishiya, Tà Âyoko Line express trains will run via the Izumino Line to station.
It has been proposed that the Tà Âkyà « Shin-Yokohama Line operate 14 trains per hour during rush hours, with 4 heading to the Tà Âyoko Line, and 10 heading to the Meguro Line. Meguro-bound Shin-Yokohama Line trains will operate through services not only to the Meguro Line, but also the Toei Mita Subway Line and Tokyo Metro Namboku Line, with further service onto the Saitama Rapid Railway Line. Once connected to the Sà Âtetsu network at Shin-Yokohama, Meguro line trains will run express along the Main Line to station.
Station numbers for the Tà Âkyà « Shin-Yokohama Line between Shin-Yokohama and Hiyoshi were revealed on 16 September 2022.
Through the end of 2022, various trainsets from Tà Âkyà «, Sà Âtetsu, Tokyo Metro, Toei, and Tà Âbu conducted tests along the now completed segment of this line and the Sà Âtetsu Shin-Yokohama Line between Hiyoshi and Hazawa Yokohama-Kokudai.
On 16 December 2022, Tà Âkyà «, Sà Âtetsu, and the Japan Railway Construction, Transport and Technology Agency announced that the Tà Âkyà « Shin-Yokohama Line would open on 18 March 2023. The Sà Âtetsu Shin-Yokohama Line section between Shin-Yokohama and Hazawa Yokohama-Kokudai also began serving at the same time. The Shin-Yokohama Line opened as scheduled on 18 March 2023, providing through service between Shin-Yokohama and Hiyoshi.
Upon opening of the line, the typical weekday off-peak services are as follows: