Keikyū Daishi Line

The line opened on 21 January 1899, built by the Daishi Electric Railway between Kawasaki Station (later Rokugōbashi) and Daishi Station (today's Kawasaki-Daishi) to carry pilgrims to the Kawasaki Daishi temple. According to Japanese sources it was the first railway in Japan running commercial service to adopt standard gauge, and the first electric-car operation in the Kantō region; English-language sources describe it as the third electric railway in Japan. It was also Japan's first dedicated pilgrimage railway, built to provide access to a shrine and temple, and its promotion of New Year visits to Kawasaki Daishi is credited with helping popularise the modern custom of hatsumōde travelling by train to famous temples. The original Kawasaki Station stood about 800 metres from the present-day station, a placement attributed to opposition from local rickshaw operators.

On 25 April 1899 the company was renamed the Keihin Electric Railway, and the whole line was double-tracked on 29 November the same year. Held up by the rickshaw operators' opposition, the line did not reach the present-day Kawasaki Station until 1 September 1902, when the section from Kawasaki to Rokugōbashi opened as part of the main line and the original terminus was renamed Rokugōbashi Station. In 1904 the track gauge was changed from 1,435 mm standard gauge to 1,372 mm to allow through service with the Tokyo streetcar network. The line proved far more profitable than the company had expected, providing the financial basis for Keihin to expand its network across the Tokyo–Yokohama corridor and influencing electric-tramway plans elsewhere in Japan.

In the 1930s the gauge was changed back to 1,435 mm standard gauge to permit through running with the Shōnan Electric Railway; Japanese sources date this re-gauging to 1 April 1933. The area along the line, once farmland and villages, was steadily turning into part of the Keihin industrial belt. A connecting line east of Daishi had originally been intended as a Keihin project, but it was instead built by a subsidiary, the Kaigan Electric Tramway, which opened between Daishi and Sōjiji in 1926; that tramway was later absorbed by the Tsurumi Rinkō Railway (today's JR Tsurumi Line) and abandoned in 1937.

During the Pacific War the line came under the wartime Dai-Tōkyū combine: under the Land Transport Business Coordination Act, Keihin Electric Railway was merged into the Tokyo Express Electric Railway on 1 May 1942, and some station names were changed for security reasons. In 1943 the line was converted from a tramway under the Tramway Act to a local railway under the Local Railway Act. To carry workers to the wartime factories of the industrial zone, the line was then extended south-east in stages, partly reusing the abandoned right-of-way of the Kaigan Electric Tramway: Kawasaki-Daishi to Sangyō-dōro opened on 1 June 1944, Sangyō-dōro to Irienzaki on 1 October 1944, and Irienzaki to Sakuramoto on 7 January 1945, completing the line through to Sakuramoto. The extension was opened as a tramway under the Tramway Act.

After the war, Keihin Electric Express Railway (Keikyū) was separated from the Dai-Tōkyū combine on 1 June 1948. The overhead voltage was raised from the original 600 V DC to 1,500 V DC on 16 March 1951, except for the Shiohama–Sakuramoto section, which was left at 600 V and into which the Kawasaki City Tram began running. In 1952 Keikyū transferred the Shiohama–Sakuramoto section to the City of Kawasaki, where it became part of the Kawasaki City Tram. The Kojimashinden–Shiohama section was suspended in 1964 to make way for the national railways' Shiohama marshalling yard (the present Kawasaki Freight Station), with Kojimashinden Station moved westward, and it was formally abolished on 20 November 1970, fixing the line in its present form. The Kawasaki-Daishi–Kojimashinden section, originally opened as a tramway, was itself converted to a local railway in 1977.

Keihin-Kawasaki Station was renamed Keikyū Kawasaki on 1 June 1987. Today the line carries only local trains, every one of them shuttling between Keikyū Kawasaki and Kojimashinden with no through service to other lines, and is operated with four-car trains because the platforms are only long enough for four cars. As part of a project to remove level crossings, the Higashi-Monzen–Kojimashinden section was moved underground on 3 March 2019, at which time the Sangyō-dōro–Kojimashinden stretch was double-tracked to complete double-tracking of the whole line; the Sangyō-dōro station was renamed Daishibashi on 14 March 2020. A second phase to put the Suzukichō–Higashi-Monzen section underground remains planned but has been delayed, and Keikyū has announced plans to introduce one-person operation on the line.

• 189921 January: the Daishi Electric Railway opens the line between Kawasaki (later Rokugōbashi) and Daishi (now Kawasaki-Daishi) to carry pilgrims to Kawasaki Daishi; stations at Kawasaki, Ikehata and Daishi open.
• 189925 April: the Daishi Electric Railway is renamed the Keihin Electric Railway. 29 November: the entire line is double-tracked.
• 19021 September: Kawasaki Station is renamed Rokugōbashi; the Kawasaki–Rokugōbashi section opens as part of the main line, reaching the present-day Kawasaki Station.
• 19041 March: the whole line is re-gauged from 1,435 mm standard gauge to 1,372 mm to enable through service with the Tokyo streetcar.
• 1925November: Kawasaki Station is renamed Keihin-Kawasaki and Daishi Station is renamed Kawasaki-Daishi.
• 19331 April: the line is re-gauged back to 1,435 mm standard gauge to allow through service with the Shōnan Electric Railway.
• 19421 May: the Keihin Electric Railway is merged into the Tokyo Express Electric Railway (the wartime Dai-Tōkyū) under the Land Transport Business Coordination Act.
• 19431 June: the line is converted from a tramway under the Tramway Act to a local railway under the Local Railway Act.
• 19441 June: Kawasaki-Daishi–Sangyō-dōro opens. 1 October: Sangyō-dōro–Irienzaki opens, extending the line south-east toward the wartime industrial zone (as a tramway).
• 19457 January: Irienzaki–Sakuramoto opens (as a tramway), completing the line through to Sakuramoto.
• 19481 June: Keihin Electric Express Railway (Keikyū) is separated from the Tokyo Express Electric Railway combine.
• 195116 March: the overhead voltage is raised from 600 V DC to 1,500 V DC except on the Shiohama–Sakuramoto section, into which the Kawasaki City Tram begins running.
• 19521 January: Keikyū transfers the Shiohama–Sakuramoto section to the City of Kawasaki, where it becomes part of the Kawasaki City Tram.
• 196425 March: the Kojimashinden–Shiohama section is suspended for construction of the national railways' Shiohama marshalling yard (now Kawasaki Freight Station); Kojimashinden Station is moved westward.
• 197020 November: the suspended Kojimashinden–Shiohama section is formally abolished, fixing the line in its present form.
• 197710 May: the Kawasaki-Daishi–Kojimashinden section, originally opened as a tramway, is converted to a local railway, making the whole line a railway.
• 19871 June: Keihin-Kawasaki Station is renamed Keikyū Kawasaki.
• 20193 March: the Higashi-Monzen–Kojimashinden section is moved underground and the Sangyō-dōro–Kojimashinden stretch is double-tracked, completing double-tracking of the whole line.
• 202014 March: Sangyō-dōro Station is renamed Daishibashi.