Company history

NHK Spring began on 6 June 1936 in Shibaura, Tokyo, as Shibaura Spring Works, capitalised at ¥600,000. Japan was in the post-Manchurian expansion and demand for leaf springs from railcars and industrial machinery was rising; the founders came out of the steel-trading and machinery worlds, and the first products were leaf springs for freight cars and bolster springs for passenger coaches. It also made leaf and coil springs for automobiles at a moment when Japan barely had an automobile industry. In September 1939, with capital coming in from Nippon Kokan, Mitsubishi Corporation and Furukawa Mining, the works was renamed Nippon Hatsujo — the company as it exists today. A small job shop had become a supplier backed by zaibatsu capital and their raw-material channels.

In November 1940 it started suspension-spring production at a new Yokohama plant and moved its base there, into the district where Nissan, Isuzu and Mitsubishi Heavy Industries built vehicles. The centre of gravity shifted from railcars to cars. Then in December 1943 it opened a plant at Ina, in Nagano, making precision springs for watches, instruments and communications equipment — because leaf-spring volume alone could not meet wartime military demand. The know-how in tens-of-micron thin springs accumulated there would, half a century later, be the technical source of the hard-disk suspension business.

The same year it absorbed Dai-Nippon Hatsujo, a precision-spring specialist in wire and thin-plate springs, broadening the range from leaf and suspension springs to a full spring line. Holding zaibatsu capital did not make it a target of the postwar dissolution, and it restarted as an independent company in the Nippon Kokan orbit, living off railcar and truck repair demand until the car industry revived. From 1953 it began pulling neighbouring firms into the group, starting with Yokohama Kiko.

NHK Spring listed on the Tokyo Stock Exchange in March 1954, giving it capital-market funding just as Toyota, Nissan, Isuzu, Mitsubishi and Honda entered volume production. The decisive year was 1958: it merged Daido Hatsujo, the second-largest spring maker in Japan, taking the plant whole from a steelmaker that could not make springs pay, and turned it into the Kawasaki works. In 1959 it did the opposite with the other end of the business, spinning the aftermarket sales arm out as Nihatsu Hanbai, a separate company that ran on stock and same-day delivery. Bring the making close, push the selling far — two moves that together settled its position as Japan’s top spring maker.

In June 1961 it opened a precision-spring shop at Kawasaki and, more consequentially, a dedicated seat plant in Toyota City, on Toyota’s doorstep. Seats are designed differently for every customer, so pooling them in a general-purpose factory was never an option; NHK Spring stayed capitally neutral and drew close to its customers in the physical unit of the plant instead. Kawasaki (1962), Hiroshima (1964) and Ota (1969) repeated the pattern across the country, and in December 1963 a joint venture in Bangkok, NHK Spring Thailand, became its first overseas plant — the seed of the later Southeast Asian network.

Industrial equipment followed: Nippon Shaft became a subsidiary in 1968, and the Atsugi plant (1970) took up piping supports. Suspension-spring capacity was extended into the Kansai region with the Shiga plant in 1973, and neighbouring firms kept being absorbed — Sumihatsu in 1975, Sanchu Akira in 1980. By the end of the 1970s a railcar leaf-spring maker had become a full-line spring company covering suspension springs, seats and precision springs, and had followed the Toyota, Nissan and Honda production networks across Japan. Already in 1968 roughly 80% of its output went to carmakers, and it accounted for close to 60% of all spring production in Japan.

The overseas build-out began in earnest in 1980 with a Spanish joint venture, Eguzkia-NHK, and ran through the North American transplant boom: NHK-Associated Spring in the United States (1986) served Honda at Marysville, Toyota in Kentucky and Nissan at Smyrna, and a 1987 tie-up with the American seat maker Lear produced General Seating of America and its Canadian twin. In South America a 1975 stake in Cimebra grew into Rassini-NHK Autopeças in 1998. Every one of these was a joint venture with a local partner rather than a solo plant — less risk, less capital tied up, and a supply base that satisfied customers’ local-content demands. Consolidation followed later: the two Spanish ventures merged in 2003, and a Dutch holding company took over European oversight in 2014.

The decisive change to the earnings structure, though, happened in Nagano. In October 1996 NHK Spring added a dedicated hard-disk suspension plant at Komagane, with a third building following in 1999. An HDD suspension is a stainless spring tens of microns thick that holds the read-write head above the platter to sub-micron tolerance — the direct descendant of the precision springs started at Ina in 1943, arriving exactly as IBM, Seagate, Western Digital, Toshiba and Hitachi entered volume production. The market settled into a duopoly with America’s Hutchinson, with NHK Spring above 60% world share, and it moved on the PC and data-centre cycle rather than the automotive one. A second core business had been built out of technology the company had kept to itself for fifty years.

On the automotive side it kept widening by partnership and acquisition. A 2001 joint venture with France’s Faurecia produced Faurecia-Nippon Hatsujo and its Kyushu arm to serve Nissan, later extended to Xiangyang in China (2012) and Indonesia. From 2002 the weight of new plants shifted to emerging Asia — a suspension-spring venture in Guangzhou, six Chinese companies in the three years from 2010, and an Indian chain running from a 1998 stake in the Jamna group to NHK Spring India in 2009. In 2012 a share exchange brought in the fastener maker Topre, adding bolts and nuts to springs, seats, precision parts and industrial equipment, while Nihatsu Hanbai was taken to full ownership the same year.

Two structural shifts then pulled the company in opposite directions. Electrification thinned the automotive parts count — suspension springs and seats survive on an EV, but engine valve springs and their like do not — and NHK Spring’s car-related businesses were left defending share in a market whose content per vehicle was falling. Meanwhile the disk-drive business, written off by many when SSDs took the PC market after 2015, was rescued by a different customer: from around 2018 data-centre nearline drives above 10TB carry more suspensions per unit and command higher prices. The DDS segment held operating margins above 20% through the 2020s.

In June 2023 Uemura Kazuhisa became president — a career insider promoted through the sales and planning organisations, as his predecessors had been. The 2026 Medium-Term Management Plan drawn up under him made portfolio management explicit: compare each segment’s ROIC against WACC, and sort businesses into growth investment, restructuring or exit accordingly. DDS came out above 20% and clearly earning its capital; seats sat near the cost of capital and were designated for restructuring; suspension springs fell below it. Alongside ¥74.5bn of R&D and capital spending, the plan committed to $400.9M (¥60bn) of shareholder returns, funded partly by unwinding the cross-shareholdings built up over decades of supplier relationships — $110.3M (¥17bn) sold against a $100.2M (¥15bn) target, with total returns reaching $437.7M (¥66bn).

The result is a company whose founding business and largest earner have swapped places. In the year ended March 2026, suspension springs turned ¥167.4bn of sales into a 0.4% operating margin and seats ¥292.5bn into 2.8%, while DDS earned $164.4M (¥26bn) on ¥126.7bn of sales — 57% of group operating profit against 27% for the three automotive segments combined. Net profit fell 42% that year on ¥11.5bn of impairments, mostly on Thai production assets, as loss-making overseas sites were cleaned up. Management is candid that leaning this hard on one business raises exposure to the data-centre cycle, and is pushing semiconductor process parts, motor cores and metal substrates as the next legs. Ninety years after the first railcar leaf spring, the profit comes from precision metal parts for data centres.