Company history

Japan Steel Works was incorporated in November 1907 at Muroran, Hokkaido, as a three-way venture between Hokkaido Colliery & Steamship and the British armament firms Armstrong Whitworth and Vickers. Under the Anglo-Japanese Alliance the government wanted naval guns and shells made at home and had neither the technique nor the capital to do it alone; the joint venture, backed by Ito Hirobumi and Matsukata Masayoshi, imported both at once. Japanese and British directors sat in roughly equal numbers on a board, and the paid-in capital was among the largest of any private manufacturer in the country. It was a private arms maker with a single customer — the Imperial Navy — and it grew fast on that one account, moving its head office to Tokyo in 1915 and opening an Osaka branch in 1918.

The geography of the company was set by the same demand. In December 1919 it absorbed the neighbouring Hokkaido Iron Works and reorganised it as the Wanishi plant, giving Muroran an integrated line from ore to forged steel; in November 1920 it bought Hiroshima Seisakusho to supply the navy's Kure arsenal with shells. The two poles that still describe the company — heavy forgings at Muroran, machinery at Hiroshima — were laid down here, the second of them as a shell factory.

Then, in the naval-limitation slump around 1930, it reversed the integration. In 1931 the Wanishi steelmaking plant was spun out as a separate company; it later passed to Japan Iron & Steel and became the Muroran works of what is now Nippon Steel — which is why a Nippon Steel blast furnace and a Japan Steel Works forge still stand side by side on the same ground. Freed of the furnaces, Muroran narrowed to gun barrels and large naval forgings, and the 10,000-tonne press installed there made it the largest and most modern private arms plant in Japan. Yokohama followed in 1936 and the Musashi works at Fuchu in 1941, building tanks for the army; from September 1938 the plants were designated controlled factories under the National Mobilisation Law, with Muroran on barrels, Hiroshima on shells and Musashi on tanks. The capacity piled up in those years is what the company would spend the next half-century dismantling.

Defeat in 1945 ended weapons production outright, and every plant was designated for reparations. The company restarted plant by plant as conversion permits came through, and in December 1950, under the deconcentration law, the old Japan Steel Works was dissolved and a new company of the same name incorporated in its place; the shares listed in Tokyo and Osaka in June 1951. What did not arrive was a replacement for the prewar business. A 150-person retrenchment followed in 1954, and for close to a decade the company felt its way as a civilian maker of cast and forged steel, petrochemical machinery and pressure vessels, without a pillar.

The turn came in 1961. A licence from the German firm Ankerwerk took Japan Steel Works into plastic injection-moulding machines, and in the same year it entered hydraulic excavators. Those two new lines carried a fresh division of labour: Hiroshima to resin machinery, Muroran to forgings and materials, Yokohama to chemical plant. Hiroshima — a shell factory in 1920 — was rebuilt around moulding and extrusion, and the machinery research laboratory opened there in January 1975 turned bought-in technology into development capacity of its own. Sales and service followed the machines abroad, with Japan Steel Works America founded in 1978 and a new Yokohama plant started in 1981.

Of the two 1961 bets, only one paid. Excavators ran into Komatsu and Hitachi Construction Machinery and lost: output was cut by 30% in September 1982 and a production and sales tie-up with IHI followed in March 1983. By the year ended March 1984 the company was in its third consecutive year of net loss.

In March 1986 the company withdrew from excavator manufacturing altogether, and four months later began cutting 600 jobs at Muroran; a further 300 followed in May 1998, 900 in all. Dismantling the arms-era capacity took the better part of twenty years, absorbing line consolidations, disposal of idle plant and long negotiation with the union. The books were carried by one-off gains rather than operations: the sale of the Tokyo works site at Fuchu, closed in 1987, produced a fixed-asset gain of $335.5M (¥43bn) in the year ended March 1992, yet by March 1994 the company was again in a third consecutive year of loss, and a recovery plan in April 2000 cut another 420 posts.

The machinery side, meanwhile, went abroad on its own account — Singapore in 1992, Malaysia and Thailand in 1996, Hong Kong in 1997, Shenzhen in 2002, Shanghai in 2008, Ningbo in 2010 — building an Asian sales and service network around injection moulding. The profits it earned there were consumed almost exactly by Muroran's structural deficit, and that offsetting became the company's defining constraint.

Chinese demand lifted orders through the late 2000s. Japan Steel Works took over Mitsubishi Heavy Industries' extruder business and acquired Tahara in November 2006, moved its head office to Shinagawa, Tokyo, in 2007, and bought the moulding-machine maker Meiki Seisakusho in 2010. At Muroran it took the opposite kind of bet: more than $679.3M (¥80bn) of new steelmaking and forging capacity aimed at large nuclear forgings, on the strength of being the only plant on earth that could produce a 600-tonne ingot.

Fukushima had already emptied the nuclear order book when, in the year ended March 2015, defects surfaced in parts supplied for wind turbines: a provision of $131.4M (¥16bn) went through as an extraordinary loss. The following year the company wrote down the fixed assets at Muroran by $325.2M (¥35bn), taking the consolidated net loss to about ¥16.6bn, and a third straight year of losses followed in March 2017. The structural problem that had recurred since the 1980s had finally arrived in a form that could not be deferred. Sato Ikuo handed the presidency to Miyauchi Naotaka in June 2016.

The answer came in April 2020. By absorption-type company split, the materials and engineering business — together with the technical arm of wind-turbine maintenance — was transferred to the subsidiary JSW M&E, while the parent kept and concentrated on industrial machinery; the compressor business went to Burckhardt and Meiki was merged into the parent. It was the first organisational separation of the founding trade of 1907 from the growth business begun in 1961, and the first division of the company since the steel spin-off of 1931.

Industrial machinery now accounts for roughly 80% of consolidated sales — a company that once sold only to the navy sells today to petrochemicals, automotive and electronics. The split itself proved provisional: an inspection scandal at the separated company came to light in May 2022, and as demand returned from nuclear restarts, defence equipment and gallium-nitride crystals, JSW M&E was merged back into the parent in April 2026, six years after it was cut out.