Honshu is a mountainous island. It also has its Alps, the Nihon Arupusu (日本アルプス) or Japanese Alps, comprising three distinct ranges, running from north to south across the island. In Toyama Prefecture there are four unique mountain railways. Two of these are commercial systems, to which a third, integrating two of the others, is to be opened to the public in 2024…
White Coal in the Devil River valley
An environmentally-questionable activity in the Nihon-Arupusu has been the exploitation of hydropower over the past century or so.
The exploitation of the hydropower resources of the Kurobegawa started in 1916, when, working with some American colleagues, Jokichi Takamine the founder of Toyo Aluminium in December 1919 with ambitions of establishing a smelter, asked the engineer Yutaka Yamada from the Ministry of Communications to conduct a field survey of the valley for the purpose of establishing various hydroelectric power stations.
Toyo Aluminium was granted water usage rights for the Kurobegawa in 1920, and the company decided to establish its main construction base in the village of Unazuku, a short way upstream from where the Kurobegawa debouches from its deep valley onto the coastal plain. A further objective was to develop the hot spring resources in Unazuki for use by company employees.
The ‘Devil River’ Railway
In 1921 Toyo Aluminium, using American capital, founded a subsidiary, the Kurobe Tetsudo (Railway), to build a 1,067mm gauge railway from Mikkaichi station (now Kurobe station) on the Hokurikuhonsen (Hokuriko Main Line - Niigata to Toyama, Tsuruga and Maibara) to Unazuki. The Kurobe Onsen Company, another Toyo Aluminium subsidiary, was founded in 1922.
The railway, inaugurated simultaneously with Uzanuki Onsen in November 1923, was also seen as the springboard for exploitation of the hydropower resources of the Kurobegawa valley. Struggling financially in the economic downturn that followed the end of the First World War, in 1922 Toyo Aluminium transferred its water usage rights to Nippon Denryoku (Nippon Electric Power, or Nichiden), which had been founded in 1919.
Nichiden's first hydropower project was in the broad valley where the Kurobegawa debouches onto the coastal Toyamaheiya (plain), about 1,5km from Aimoto station on the Kurobe Tetsudo from Mikkaichi to Unazuki Onsen, in the Nakanoguchi district. The power station started producing electricity on 4 June 1936, and had a design maximum output of 30,700kW.
Presumably Aimoto was known in its early days as Kurobegawa Daiichi (First). Upstream from here the numerical sequence (First to Fourth) is interrupted by the later construction of hydropower complexes at Otozawa, Unazuki and Yanagigawa, of which more anon. Downstream from Aimoto there are also six small hydropower stations on the Toyama-heiya, Kuronishi Daiichi, Daini and Daisan (Kuro-West First to Third) and Kokuto (Black East Water) Daiichi, Daini and Daisan, developed during the 1920s and 1930s. All can be located on Google Maps.
Upstream from Unazuki, with its increasing number of hotels and onsens, various locations were identified as suitable sites for dams, and in 1924 Nichiden started building a 762mm gauge railway between Unazuki Onsen, altitude 224m, and Nekomata (‘猫又’), altitude 358m. The origins of the latter name are interesting. A nekomata has eyes like a cat, and a large, dog-like body, lives in the mountains, and by tradition eats humans. It is, essentially a ‘cat monster’ or ‘devilcat’. Even more bizarrely it can shape-shift into humans. So the story goes, a nekomata once chased a rat (or mouse) here. The rat headed for a 200m high cliff (on the north side of the power station building), but found it too steep to scramble up. The cliff is known in Japanese as Nezu mi-gaeshi no ganpeki (ねずみ返しの岩壁 - ‘the mouse-guard rock wall’).
The trackbed followed the route of an old forestry path. During the construction period an overhead wire was rigged up and a batch of two-axle single-cab locomotives, EB1 to 3 and 5 to 7, later joined by EB12, was acquired from Jeffrey Manufacturing of Columbus, Ohio. In 1959 they were modified with their trolley current-collection poles being replaced by cab-mounted pantographs. Jeffrey was the first American company to build electric locomotives for use underground in coal mines, in 1888, and by the 1920s was already a supplier of such machines to Japan.
This initial 11.8km stretch of railway was ready for use, for the transport of materials required for dam and power station construction, on 23 October 1926. Construction of the first HEP complex, Yanagigawara, just upstream from Uzanuki, began in 1924 with completion in 1927, but was hampered by floods and landslides. The dam at Nekomata was also completed in 1927, to provide water for Yanagigawara.
A further power station, Kurobegawa Daini (Second), was built at Nekomata betwen 1933 and 1936 This is situated on the left bank of the river, accessed by a siding which leaves the main line in tunnel, on the left bank, north of Nekomata station.
In 1925 Nichiden decided to explore further up the valley. While it was reckoned that in the future the railway could be extended to Keyakidaira, upstream from there construction would be extremely costly if not impossible. First, a 13km path, known as the Suihei Hodo was built high above the left bank of the Kurobegawa upstream from Keyakidaira to Sennindani, together with a refuge hut at Asohara Onsen. Then, a 16.6km path, known nowadays as the Nichiden Sendo, was carved out of the precipitous mountainside, on the left bank of the Kurobegawa, but following the river more closely. In 1929 these paths were usable as far as the refuge hut at Hirano, just downstream of the site earmarked for the future construction of the world-famous Kurobe dam. They vary in width between 500 and 800mm, and in places timber staging is used to provide a sort of vertiginous boardwalk above the river, where the cliffs are almost sheer. Handrails are provided in places.
When the Chubusangaku National Park was established, one of the conditions was that Nichiden and its successors were obliged to continue the annual maintenance of the Suihei Hodo and Nichiden Sendo, so that they could be used by walkers. Although the paths could be used for the transport, on foot, of light construction materials, it would be impossible to transform them into a road or railway. On account of the severe winter climate, the paths are only accessible for a period of a month or two, in autumn, between the melting of the previous winter's snows and the first snowfall of the coming winter. So steep-sided and deep
