IHI Corporation, the Engine Maker Behind Japan’s Air Power

IHI Corporation builds the engines inside virtually every Japanese military aircraft, from the P-1’s four F7 turbofans to the XF9 demonstrator that fed Japan’s sixth-generation fighter bid, on revenue of roughly ¥1.6 trillion a year. The company that began as an 1853 shipyard is now Tokyo’s propulsion house, and one leg of the three-nation GCAP fighter engine team.

1853

Founding of the Ishikawajima shipyard, IHI’s origin

~¥1.6T

Annual revenue, roughly $11 billion

4

F7 engines on every Kawasaki P-1 patrol jet

3

Nations in the GCAP engine partnership, Japan, UK, Italy

IHI Corporation at a glance

Company fact sheet

Item	Detail
Full name	IHI Corporation, formerly Ishikawajima-Harima Heavy Industries
Headquarters	Tokyo, Japan
Founded	1853 as the Ishikawajima shipyard; 1960 merger created Ishikawajima-Harima; renamed IHI in 2007
Employees	Around 28,000–29,000 group-wide
Revenue	Roughly ¥1.6 trillion (about $11 billion) in recent fiscal years
Ownership	Publicly listed on the Tokyo Stock Exchange (7013)
Main fields	Aero engines, space and defense systems, turbochargers, energy and industrial plants

Figures rounded from public company disclosures.

IHI’s aero engine, space and defense segment has become the group’s profit engine as Japan’s military buildup and the civil aviation recovery arrived together. The company holds shares in major civil programs, the V2500, GEnx and PW1100G among them, work that keeps its turbine factories at scale between defense orders.

What does IHI make

Beyond engines, IHI builds solid rocket motors and launch vehicles through IHI Aerospace, turbochargers for the world’s carmakers, and energy and infrastructure plants. The defense portfolio also includes torpedo and missile propulsion work and naval machinery. But propulsion is the identity, in Japan’s aerospace division of labor, Mitsubishi Heavy Industries integrates the airframes and IHI supplies the thrust.

IHI military jet engines

IHI military engine lines

Engine	Application	Notes
F3	T-4 trainer	First mass-produced indigenous turbofan, about 640 built with spares
F7-10	Kawasaki P-1, four per aircraft	High-bypass turbofan designed for low-altitude maritime patrol
F100 and F110	F-15J and F-2 fighters	License production of Pratt & Whitney and GE designs
XF5-1	X-2 Shinshin technology demonstrator	Compact afterburning turbofan that proved domestic fighter-engine skills
XF9-1	Fighter engine prototype	Demonstrated 15-ton-class thrust with slim core; groundwork for GCAP

License-built engines are produced under agreements with their US designers.

The XF9 deserves the attention it gets. Delivered in 2018, the prototype demonstrated thrust in the 15-ton class with afterburner from a deliberately slender core, per official statements, proof that Japan could design a modern low-observable-friendly fighter engine after decades of license building. It was never meant for production, it was meant as a bargaining chip, and it worked.

IHI and the GCAP fighter engine

When Japan merged its F-X fighter program with the UK-Italian Tempest effort to form the Global Combat Air Programme, IHI became one third of the joint engine team alongside Rolls-Royce and Italy’s Avio Aero. The three firms are developing the combat engine for the 2035-target fighter, with IHI contributing the XF9 lineage, hot-section materials and Japan’s ceramic matrix composite work. For a company that spent seventy years license-building American fighter engines, co-designing a first-rank combat powerplant with Rolls-Royce is the largest step up in its history, mirroring the airframe partnership described in our look at Asia’s new fighters.

IHI Aerospace, rockets and defense growth

IHI Aerospace, the group’s Gunma-based space arm, builds the Epsilon small launcher and the solid rocket boosters for Japan’s H3, and its solid-motor expertise flows directly into the missile programs at the center of Tokyo’s standoff defense buildup. The company has publicly flagged a surge in defense orders since 2023, including propulsion work tied to Japan’s extended-range missile programs, and has announced capacity expansion at its engine and rocket plants. Like the rest of Japanese industry it must now deliver against a weak yen, tight engineering labor and export rules that are loosening only gradually.

Editor’s read

IHI is the quietest of Japan’s defense majors and arguably the most strategically placed. Fighter programs can slip and shipbuilding can be shared, but nobody else in Japan can make a combat aircraft engine, and GCAP has converted that monopoly into a seat at a three-nation table. The risk worth watching is concentration, the aero engine segment now carries the group’s profits, so a GCAP delay or a civil aviation shock would land hard.

IHI Corporation frequently asked questions

What does IHI stand for?

Ishikawajima-Harima Heavy Industries, the name carried from the 1960 merger until the company formally became IHI Corporation in 2007.

What engines does IHI make for Japan’s military?

The F3 for the T-4 trainer, the F7-10 for the P-1 patrol aircraft, license-built F100 and F110 fighter engines, and the XF5 and XF9 demonstrator engines.

Is IHI part of the GCAP fighter program?

Yes. IHI develops the GCAP combat engine jointly with Rolls-Royce and Avio Aero for the Japan-UK-Italy fighter targeted at 2035.

Does IHI build rockets?

Yes, through IHI Aerospace, which produces the Epsilon launcher, H3 solid boosters and solid rocket motors that support Japan’s missile programs.

How big is IHI?

Roughly ¥1.6 trillion in annual revenue, about $11 billion, with around 28,000 employees, and aero engines, space and defense as the leading profit segment.

Sources