Keihan Ishiyama Sakamoto Line

The line began as a project of the Ōtsu Electric Tramway (Ōtsu Densha Kidō). Its first segment, between Ōtsu Station — today's Biwako-Hamaōtsu — and Zeze (the present Zeze-honmachi), opened on 1 March 1913, with the stretch from Ōtsu to Baba sharing tracks with a government freight line; the segment on to Beppo (now Awazu) followed on 1 May 1913. The line was then extended south in stages through the first half of 1914, reaching Hotarudani in February and finally Ishiyama — now Ishiyamadera — on 4 June 1914, completing the original Ōtsu-to-Ishiyama route as a single-track tramway.

Development continued northward in the 1920s. The Hamaōtsu–Miidera section opened on 7 May 1922. On 21 January 1927 the Ōtsu Electric Tramway merged with the lake-steamer operator Taiko Kisen to become the Biwako Railway & Steamship Company (Biwako Tetsudō Kisen). That company pushed the line north along the lakeshore toward Sakamoto, opening successive segments through 1927, and on 10 September 1927 the Heiei-mae–Sanjō section opened, completing through running between Ishiyama and Sakamoto.

Keihan Electric Railway absorbed the Biwako Railway & Steamship Company on 11 April 1929, transferring the steamship business back to Taiko Kisen and keeping the railway. Under Keihan the two halves of the route were operated as the Ishiyama Line and the Sakamoto Line, and from 5 October 1931 through trains ran between Ishiyama and Sakamoto, ending the need to change at Miidera. On 20 June 1939 a connecting line to Keihan's Keishin Line was completed at Hamaōtsu, tying the Ōtsu network together.

The wartime years left a lasting mark on the line's double-tracking. The Ishiyama-ekimae–Awazu section was double-tracked on 20 August 1943, but on 30 March 1945 the Shigasato–Sakamoto section was reduced to single track and its second set of rails surrendered for the metal demands of the war effort. Re-doubling came only gradually: the Shigasato–Anō stretch was restored to double track in March 1947, while the final segment, Anō–Sakamoto, was not re-doubled until 30 September 1997 — fifty-two years later — an event that completed the double-tracking of the entire Keihan network.

The corporate identity of the line shifted repeatedly around the war. On 1 October 1943 a company merger placed it under Keihanshin Express Electric Railway (the predecessor of today's Hankyu Corporation), and on 1 December 1949 a corporate separation returned it once more to Keihan Electric Railway. On 10 January 1956 the Ishiyama Line and the Sakamoto Line were unified and renamed as a single Ishiyama Sakamoto Line, the name the route still carries.

The line's electrification was modernised at the end of the century in step with the Keishin Line. After test running during 1997, the overhead voltage was raised from 600 V to 1,500 V DC on 12 October 1997, carried out in conjunction with the Keishin Line's voltage upgrade for its through service into the Kyoto Municipal Subway Tōzai Line; the change allowed newer air-conditioned, regenerative-braking stock to take over and ended the use of older cars on the route.

In its modern role the Ishiyama Sakamoto Line is an Ōtsu commuter and sightseeing line, all trains running as two-car local services. It links residential and industrial districts — factories of firms such as Toray and Nippon Electric Glass line the route — with Ōtsu City Hall and numerous schools, while also carrying visitors to shrines and temples including Ishiyama-dera, Miidera, Ōmi-jingū and Hiyoshi Taisha. One-man operation was introduced on 4 October 2003, and on 17 March 2018 four stations were renamed, with Hamaōtsu becoming Biwako-Hamaōtsu and the northern terminus Sakamoto becoming Sakamoto-Hieizan-guchi.

• 19131 March: the Ōtsu Electric Tramway opens its first segment, Ōtsu (now Biwako-Hamaōtsu) to Zeze (now Zeze-honmachi); the Ōtsu–Baba stretch shares a government freight line. On 1 May the Zeze–Beppo (now Awazu) segment opens.
• 1914The line is extended south in stages, reaching Hotarudani on 15 February and finally Ishiyama (now Ishiyamadera) on 4 June, completing the original Ōtsu–Ishiyama route as single track.
• 19227 May: the Hamaōtsu–Miidera section opens.
• 192721 January: the Ōtsu Electric Tramway merges with the steamer operator Taiko Kisen to form the Biwako Railway & Steamship Company. On 10 September the Heiei-mae–Sanjō segment opens, completing through running between Ishiyama and Sakamoto.
• 192911 April: Keihan Electric Railway absorbs the Biwako Railway & Steamship Company, transferring the steamship division back to Taiko Kisen and keeping the railway.
• 19315 October: through running begins between the Ishiyama Line and Sakamoto Line, ending the transfer at Miidera.
• 193720 August: stations are renamed; Hotarudani is merged into Ishiyama and renamed Ishiyamadera, and Zeze is renamed Zeze-honmachi.
• 193920 June: a connecting line to Keihan's Keishin Line is completed at Hamaōtsu, tying the Ōtsu network together.
• 194320 August: the Ishiyama-ekimae–Awazu section is double-tracked. On 1 October a company merger places the line under Keihanshin Express Electric Railway (predecessor of Hankyu).
• 194530 March: the Shigasato–Sakamoto section is reduced to single track and its rails surrendered for the wartime metal effort.
• 1947March: the Shigasato–Anō section is restored to double track.
• 19491 December: a corporate separation returns the line once more to Keihan Electric Railway.
• 195610 January: the Ishiyama Line and the Sakamoto Line are unified and renamed the Ishiyama Sakamoto Line.
• 199730 September: the Anō–Sakamoto section is re-doubled after 52 years, completing the double-tracking of the entire Keihan network. On 12 October the overhead voltage is raised from 600 V to 1,500 V DC, in step with the Keishin Line's upgrade for through running into the Kyoto Municipal Subway Tōzai Line.
• 20034 October: one-man operation begins on the line.
• 201817 March: four stations are renamed — Hamaōtsu to Biwako-Hamaōtsu, Beppo to Ōtsu-shiyakusho-mae, Kōjiyama to Keihan-Ōtsukyō, and the northern terminus Sakamoto to Sakamoto-Hieizan-guchi.