Company history

Yamato Kogyo was founded in November 1944 in Mikuni village, Shikama district, Hyogo — today part of Himeji — by Inoue Asaji, with capital of ¥198,000, as a subcontractor to Kawanishi Aircraft. Himeji sat at the western end of the Hanshin industrial belt alongside Kobe Steel and Kawasaki Heavy Industries; the company existed because wartime demand was concentrated there. When the war ended nine months later, that demand vanished with it.

In August 1945 the company turned its whole output to making and repairing track hardware for Japanese National Railways and the private railways. The pivot was not a change of technology but a change of customer: the same metalworking skills, aimed at a different buyer. Track fittings were cheap, unglamorous parts, but as long as trains ran they wore out, and the repair-and-replacement orders never stopped. Around that steady base the company built a sales network — a Tokyo office in 1948, a rebuilt head plant on Hinode-cho in Himeji in 1949, an Osaka office in 1951 — and won JIS-certified plant status in 1953.

Making track hardware cheaply and reliably meant controlling the steel itself. In July 1956 Yamato Kogyo bought the site of a former military aircraft-ordnance works at Niibono in Himeji and began producing steel ingots; the head plant moved there in 1957, cast steel followed in 1958, and in November 1959 the company installed a 15-tonne Héroult electric furnace of its own design. From that furnace onward, everything Yamato Kogyo did was built on electric-furnace steelmaking.

In April 1960 a large-section rolling mill completed the chain from furnace to finished bar, making Yamato Kogyo the only fully integrated maker of track fittings in Japan and giving it a near-monopoly in that niche. Capital markets followed: an over-the-counter listing in Osaka in November 1960, in Tokyo in September 1961, and in October 1961 a simultaneous second-section listing on the Tokyo, Osaka and Kobe exchanges. A year later, in September 1962, the shares moved to the first section. The build-out was funded by relentless equity issuance — ten capital increases in thirteen years, from ¥1 million in January 1948 to ¥1.3 billion in May 1962.

Production then consolidated at a new site in Aboshi: a 40-tonne electric furnace in December 1961, plate rolling in January 1962, the head office itself in August 1962. The same years brought deliberate diversification away from a single product. A structural-steel and bridge division opened in September 1962, expanded metal in March 1963; plate production was scrapped in 1968 to concentrate on forging; the switch-and-crossing business of Osaka Seisa Zoki was acquired in May 1969, and a heavy-machining division added that November.

By 1974 the mix told the story: large sections 51.6%, crude steel 27.7%, track fittings just 13.3%, heavy machining 7.3%. The founding product had become a minor line. The decisive addition came in November 1975, when a universal mill took the company into H-beams — the product that would define it. Continuous casters in 1973 and 1978, a second 50-tonne furnace, in-house beam-blank production from June 1980 and ladle refining in February 1987 steadily pushed cost and quality in H-beams to a competitive level. Leadership passed from the founder to Inoue Junichi and, in December 1981, to his grandson-generation successor Inoue Hiroyuki, the third Inoue to run the firm.

Domestic track-fitting demand had stopped growing, and even in H-beams Yamato Kogyo was too small to fight the integrated blast-furnace giants alone. Its answer, in February 1987, was Nucor-Yamato Steel — a joint venture with the largest electric-furnace steelmaker in the United States, in which Yamato Kogyo took only 49%. It offered the one thing it had, H-beam technology, in exchange for a partner who understood the American market, and it did not ask for control. A US holding company had been set up a month earlier; Arkansas Steel Associates followed in 1989 with the Sumitomo Corporation group.

The same formula was then carried across Asia and the Gulf: Siam Yamato Steel in Thailand in April 1992, with Siam Cement, Mitsui & Co. and Sumitomo Corporation; Yamato Korea Steel in November 2002, which took over the operations of the failed Hanbo Busan works; United Steel Company (SULB) in Bahrain in 2009 and United Sulb in Saudi Arabia in 2011, both with Foulath. Each venture put Yamato Kogyo alongside the strongest local player rather than against it. At home, a 130-tonne DC electric furnace replaced the older units in 1996.

The corporate form eventually caught up with the strategy. Track fittings were spun off in April 2002, and in October 2003 the steel and heavy-machining businesses became Yamato Steel, leaving the parent as a pure holding company whose job was to manage stakes rather than run plants. Thailand was consolidated as a subsidiary in June 2007 and doubled its capacity with a second mill in 2010. In June 2017 Inoue Hiroyuki moved up to chairman and Kobayashi Mikio, who had come from Mitsui & Co.’s Americas steel business in 2012, became president — the first non-family chief executive. By FY2018–19 the shape was settled: sales of ¥182–201 billion, recurring profit of ¥23–32 billion, and most of that profit arriving from overseas ventures the company did not consolidate.

The portfolio was pruned and re-aimed. In March 2020 Yamato Kogyo and its Thai subsidiary jointly bought 49% of POSCO SS Vina in Vietnam, renamed POSCO-Yamato Vina; that September the Korean bar business was sold down to Daehan Steel, an effective exit from Korea that helped drive an extraordinary loss of ¥9.8 billion and cut FY2020 net profit to ¥4.9 billion. The company moved to the Prime Market in April 2022 and set out a plan, NEXTRA2024, built on regional diversification and the low-CO₂ advantage of electric-furnace steel.

Then came the best three years in the company’s history — for reasons largely outside its own gates. Rising North American steel prices and a rapidly weakening yen inflated the equity-method income from Nucor-Yamato, lifting recurring profit to ¥57.6bn, ¥90.4bn and ¥99.2bn in FY2021–23, with FY2023 net profit reaching $498.2M (¥70bn). In May 2024 the company and Siam Yamato took 80% of an Indonesian maker, renamed PT Garuda Yamato Steel and consolidated it — the newest node in a three-region hub strategy spanning the Americas, Southeast Asia and the Gulf. Consolidated headcount jumped from 1,414 to 2,585 in a single year.

FY2024 showed both sides of the model. Sales of ¥168.3bn produced operating profit of only ¥11.5bn, while non-operating income — chiefly equity-method earnings from ventures the company does not control — came to ¥43.6bn, carrying recurring profit to $359.1M (¥54bn) and net profit to ¥31.8bn. That is a steep fall from the FY2023 peak, and it moved with American prices and the exchange rate rather than with anything Yamato Kogyo rolled. Ownership has stayed close: the Inoue family and its vehicles held roughly 22% as of June 2025, with Mitsui & Co. at 7.2%.