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Nihonkai Hisui Line

日本海ひすいライン

The Nihonkai Hisui Line (日本海ひすいライン, "Sea of Japan Jade Line") is a 59.3-kilometre railway line operated by the third-sector Echigo Tokimeki Railway in the southwest of Niigata Prefecture, running along the Sea of Japan coast from Ichiburi, near the boundary with Toyama Prefecture, through Itoigawa to Naoetsu in the city of Jōetsu. Laid to 1,067 mm narrow gauge and double-tracked throughout, it has 13 stations. Its most distinctive feature is its split electrification: the section toward Ichiburi is electrified at 20 kV 60 Hz AC while the section toward Naoetsu is at 1,500 V DC, with a dead section between the two. Rather than buy costly dual-voltage trains, the operator runs most local services with diesel railcars across the gap. The line is the former Niigata-side stretch of JR West's Hokuriku Main Line, handed over when the Hokuriku Shinkansen reached Kanazawa in 2015.

Route of the Nihonkai Hisui Line · Prefectures: MLIT

History

The corridor was built piecemeal by the national railways in the early 1910s, partly as a branch of the Shin'etsu Line and partly as an extension of the Hokuriku Main Line. The Shin'etsu Line branch from Naoetsu to Natadachi, about 14.81 km, opened on 1 July 1911. The following year the Hokuriku Main Line was extended on 15 October 1912 from Tomari, in what is now Toyama Prefecture, to Ōmi, a stretch of about 23.34 km that brought Ichiburi and Ōmi onto the map, and on 16 December 1912 the Shin'etsu Line branch was pushed on from Natadachi to Itoigawa, about 26.55 km.

The gap was closed on 1 April 1913, when the roughly 6.6 km between Ōmi and Itoigawa opened and the Hokuriku Main Line from Maibara to Naoetsu was completed end to end; the formerly separate coastal sections were unified under the Hokuriku Main Line name. The new line clung to a rugged, avalanche-prone coast, and it was the scene of two of the deadliest accidents in Japanese railway history: a landslide between Nō and Kajiyashiki on 20 July 1913 killed three people, and an avalanche that struck a train between Oyashirazu and Ōmi on 3 February 1922 killed around ninety.

For half a century the line remained a steam-worked single-track coastal main line. Double-tracking and electrification came together in the 1960s. The Tomari–Itoigawa section was electrified with alternating current and partly double-tracked from 30 September 1965, and further double-tracking followed in 1966. The work was completed on 1 October 1969, when a relocated, double-tracked alignment opened between Tanihama and Naoetsu, the old Gōzu station was closed, and the Itoigawa–Naoetsu section was electrified with direct current — leaving the line fully double-tracked and electrified but split between AC and DC supplies.

With the privatisation and break-up of the Japanese National Railways on 1 April 1987, the line passed to the West Japan Railway Company (JR West) as part of the Hokuriku Main Line. It remained a JR West trunk route for the next twenty-eight years, carrying long-distance limited expresses along the coast between the Hokuriku region and Niigata as well as freight and local traffic.

The decisive change came with the Hokuriku Shinkansen. When the high-speed line was extended to Kanazawa on 14 March 2015, JR West discontinued the parallel conventional Hokuriku Main Line between Kanazawa and Naoetsu, a distance of about 177.2 km. The Niigata-Prefecture portion from Ichiburi to Naoetsu, 59.3 km, was transferred to the newly established Echigo Tokimeki Railway and renamed the Nihonkai Hisui Line. To avoid the expense of procuring new dual-voltage rolling stock for the AC/DC boundary, the company introduced a fleet of single-car ET122 diesel railcars for most local services.

Since the transfer the line has continued to evolve. On 13 March 2021 a new station, Echigo-Oshiage-Hisui-Kaigan, opened between Itoigawa and Kajiyashiki on the stretch where the line changes electrical systems. Today the Nihonkai Hisui Line functions as a local coastal railway serving the Itoigawa and Jōetsu areas, with connections to the Hokuriku Shinkansen at Itoigawa and to JR East and the Echigo Tokimeki Railway's own Myōkō Haneuma Line at Naoetsu.

Timeline
  • 19111 July: the Shin'etsu Line branch from Naoetsu to Natadachi (about 14.81 km) opens.
  • 191215 October: the Hokuriku Main Line is extended from Tomari to Ōmi (about 23.34 km), opening Ichiburi and Ōmi.
  • 191216 December: the Shin'etsu Line branch is extended from Natadachi to Itoigawa (about 26.55 km).
  • 19131 April: Ōmi–Itoigawa (about 6.6 km) opens, completing the Hokuriku Main Line from Maibara to Naoetsu; the coastal sections are unified as the Hokuriku Main Line.
  • 191320 July: a landslide between Nō and Kajiyashiki kills three people.
  • 19223 February: an avalanche strikes a train between Oyashirazu and Ōmi, killing around ninety (the Hokuriku Line train avalanche accident).
  • 196530 September: the Tomari–Itoigawa section is electrified with AC and partly double-tracked.
  • 19691 October: a relocated double-track alignment opens between Tanihama and Naoetsu (Gōzu station closed) and Itoigawa–Naoetsu is electrified with DC, completing double-track electrification of the whole line.
  • 19871 April: with the privatisation of the Japanese National Railways, the line passes to JR West as part of the Hokuriku Main Line.
  • 201514 March: when the Hokuriku Shinkansen opens to Kanazawa, JR West discontinues the Kanazawa–Naoetsu conventional line (177.2 km); Ichiburi–Naoetsu (59.3 km) transfers to Echigo Tokimeki Railway and is renamed the Nihonkai Hisui Line, with single-car ET122 diesel railcars introduced for most local services.
  • 202113 March: Echigo-Oshiage-Hisui-Kaigan station opens between Itoigawa and Kajiyashiki, on the stretch where the line changes electrical systems.

Sources

Facts last verified 14 June 2026.

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