Company history

Japan began generating electricity commercially in 1886, and as transmission lines lengthened year after year the demand for insulators rose with them — every one of them imported from the United States and Britain. In the spring of 1905 Kishi Keijiro of Shibaura Engineering Works (later Toshiba) brought back a fragment of an insulator from the American firm Thomas, showed it to Okura Kazuchika, president of Nippon Toki, and urged him to make them in Japan. Okura took it up on terms that were not commercial — this was to be done, he said, as a service to the country rather than for profit — and in 1907 the first 15kV insulators went to Shibaura.

Demand grew with the electricity industry, and in May 1919 Okura, Morimura Kaisaku and six other founders carved the insulator division out of Nippon Toki as a separate company in Nagoya, capitalised at ¥2 million. Within the Morimura group the division of labour then set: Nippon Toki (now Noritake) made tableware, NGK made industrial ceramics. The new company sold high-voltage insulators and bushings to one class of customer — the electric utilities — and built out around them: American Harrop tunnel kilns and a 1,000kV test rig in the 1920s, branch offices in Tokyo, Osaka, Fukuoka, Sendai and Sapporo, staff sent to the United States, Canada and India, and from 1922 acid-resistant porcelain equipment for the emerging chemical industry. In 1936 the spark-plug division was itself spun off, as NGK Spark Plug.

War broke the pattern that fed it: with materials scarce the utilities stopped building lines, and NGK survived as a maker of military communication insulators and acid-resistant ware, designated a munitions company in 1944. Exports resumed from 1948 to India, the United States, Australia and Sweden; the shares were listed in Tokyo, Nagoya and Osaka in May 1949. Then public money poured into power development from the Korean War onward, and NGK built to meet it — the Atsuta plant in 1957, Komaki in 1962 — until its insulator output stood at world scale. The engine of that growth, however, was entirely Japan’s electricity infrastructure budget, and nothing else.

Selling one product to one industry meant that revenue simply tracked the utilities’ capital spending. The first long-range plan, launched in 1964, put a number on the way out: six parts insulators to four parts everything else. The reasoning was that with Atsuta and Komaki complete the insulator business had reached the scale of a world leader, so further growth had to be sought in adjacent fields — and the fields were chosen to be adjacent on purpose. Water and sewage treatment had grown out of porcelain diffuser plates; chemical-plant equipment out of acid-resistant ware; beryllium copper had reached industrial production in 1958.

The groundwork was already laid. President Nobuchi Sanji had introduced a divisional structure on taking office in 1959, with chemical-equipment and new-product divisions; in 1962 the company licensed rapid-filtration underdrain technology from Leopold of the United States and became a plant contractor in water, sewage and sludge treatment, selling environmental equipment from 1963. What the 6:4 plan really fixed was therefore not a quantity of diversification but a boundary: only what the insulator kiln and the acid-resistant sales channel could reach counted as growth territory.

As a numerical target it failed outright. A decade on, in the year to March 1974, power-related products still accounted for 94% of sales, and a later president, Shibata Masaharu, said the goal took twenty years to reach. Meanwhile the insulator business itself went abroad and up in voltage: one-piece bushings for 500kV substations in 1965, high-strength suspension insulators for ultra-high-voltage lines from 1966; NGK America (now NGK-LOCKE) in 1965, NGK Canada in 1968, and in 1973 a Baltimore joint venture with General Electric, Locke Insulators, that began making insulators on the ground rather than shipping them from Japan.

The United States passed the Clean Air Act — the Muskie Act — in 1970, and NGK began developing a ceramic honeycomb substrate to carry catalysts in exhaust systems. In 1976 it landed Ford and commercialised automotive ceramics that same year. This was the 6:4 plan’s decisive success, and its importance was structural: insulator volumes moved with utility investment, while honeycombs moved with world car production, which meant NGK could finally take demand growth from outside Japan directly.

The company then built where cars were built — NGK Europe in Germany in 1976, NGK Ceramics Europe in Belgium in 1985, NGK Ceramics USA in 1988, then Indonesia in 1996, Suzhou in 2001, Poland in 2003 and Mexico in 2008. Belgium had arrived a decade earlier by a different route: in 1977 NGK bought a working Belgian insulator maker outright, plant and workforce, as NGK-BAUDOUR. Insulator production there eventually disappeared, but the site and its people decided where the European automotive ceramics plant would go — an overseas foothold outliving the business that created it. In 1986 the company rewrote its Japanese name from the kanji 日本碍子 into katakana 日本ガイシ to sit alongside the NGK brand abroad; by then the business had already left insulators behind.

Other bets ran alongside: beryllium copper localised in the US as NGK Metals in 1986; in 2002 the world’s first commercial NAS sodium-sulphur storage batteries for grid-scale storage, and a stake in FM Industries, a maker of modules for semiconductor production equipment — the seed of what later became the Digital Society segment. The year to March 2008 marked the peak of the era at $3.5B (¥365bn) in sales and $670.7M (¥69bn) in operating profit. Then the financial crisis cut sales 25% the following year, and in September 2011 an NGK-made NAS battery caught fire at Mitsubishi Materials’ Tsukuba works: shipments were halted worldwide, and the year to March 2012 carried an extraordinary loss of $819.7M (¥65bn) and a net loss of $446.2M (¥36bn). The world’s first product of its kind had been forced, ten years in, into a long campaign to win back trust.

Oshima Taku took the presidency in June 2013 with two jobs at once: repair the NAS business and ride the growth in automotive and semiconductor ceramics. In January 2015 NGK bought Nippon Steel & Sumikin Electronic Devices outright, taking in ceramic semiconductor packaging, while the automotive network kept widening — Thailand, a second Polish plant in 2017, a second Suzhou plant in 2019. Sales recovered from $2.9B (¥309bn) in the year to March 2014 to $4.0B (¥436bn) two years later and $4.1B (¥451bn) in the year to March 2018, by which point the businesses that were not insulators were carrying the whole company.

In January 2019 the Tajimi plant of NGK Ceramic Device began operating, dedicated to parts for semiconductor production equipment, and that became the centre of gravity. Kobayashi Shigeru succeeded Oshima in April 2021 and published the “NGK Group Vision — Road to 2050” the same month, setting carbon neutrality and the digital society as the two pillars and targeting, for the year to March 2026, $3.8B (¥600bn) in sales, $569M (¥90bn) in operating profit and a 10% return on equity — plus “NV1000”, ¥100 billion of sales from new businesses by 2030, drawn from direct air capture, sub-nano ceramic membranes, green energy, next-generation composite wafers and high-temperature ceramic carriers. A company named for insulators had put in writing that it was, instead, a ceramics company.

The limits showed quickly. In the year to March 2024 a weak yen carried sales to a record $3.8B (¥579bn), but operating profit slipped 1% and net profit fell 26% after impairments in ceramic packaging, hit by the slump in Chinese smartphones. The three pillars — Environment (auto honeycombs), Digital Society (semiconductor and electronic parts) and Energy & Industry (insulators and NAS) — each run on their own cycle, so a fall in one is usually covered by another, but all three rarely rise together, and the 2025 operating-profit target moved out of reach. In February 2025 NGK contracted to buy Germany’s Deutsche KNM, owner of BORSIG, for about €270 million, to acquire the engineering and the customers needed to sell its sub-nano ceramic membranes as systems rather than as material — buying the carbon-neutral business instead of building it. The deal was called off in January 2026 when conditions tied to the seller’s parent going private were not met.