Japanese representatives receive World War II-era Imperial Japanese Army Air Service aircraft artifacts at Yokota Air Base, Japan, July 1, 2026. The artifacts were discovered during a construction project on the installation and were transferred for continued research and preservation. (Kaori Matsukasa/U.S. Air Force)
YOKOTA AIR BASE, Japan — A trove of artifacts unearthed recently at a construction site revealed a page from the World War II-era history of this airlift hub in western Tokyo.
Formerly known as Tama Army Airfield, Yokota Air Base served as a testing site for numerous Japanese aircraft during World War II, according to a story posted July 7 on the Defense Department website.
The artifacts were first discovered in January during work at a site that was formerly occupied by Hangar 800, which was demolished in 2020.
The hangar was originally built in 1939 by the Imperial Japanese Army Air Service and housed a variety of aircraft.
At the time, no one could identify the objects — unearthed from 7-10 feet beneath the surface — so some of them were removed for further examination, Callie Oldfield, an environmental scientist for the 374th Civil Engineer Squadron, told Stars and Stripes in an interview Thursday.
“I got the call to assess them as unidentified objects in my role as the environmental program manager,” she said.
Callie Oldfield, 374th Civil Engineer Squadron environmental scientist, packs a World War II-era Imperial Japanese Army Air Service aircraft component into a box for transport at Yokota Air Base, Japan, July 1, 2026. (Kaori Matsukasa/U.S. Air Force)
World War II-era Imperial Japanese Army Air Servcie aircraft artifacts are displayed at Yokota Air Base, Japan, July 1, 2026. (Yasuo Osakabe/U.S. Air Force)
After an initial assessment by the Fussa City Board of Education, a team of experts from the Gifu-Kakamigahara Air and Space Museum were contacted to thoroughly examine the artifacts, according to a news release July 1 from the 374th Airlift Wing.
The experts identified the artifacts as aircraft parts from a Kawasaki-made aircraft, the Ki-61 Hien, Ki-45 Toryu and Ki-102 Otsu.
The Ki-61 Hien fighter, called Tony by the Allies, was the only mass-produced Japanese fighter of World War II with a liquid-cooled engine, according to militaryaviationmuseum.org. Its pilots sometimes rammed their aircraft into U.S. B-29 Superfortress bombers.
The Ki-45, or Nick, was the only Japanese army night fighter to see action during the war, according to the National Air and Space Museum website. The Ki-102 Randy was a twin-engine, two-seat attack aircraft introduced too late in the war to see much service, according to aviastar.org.
Some of the discovered parts are extremely rare and among few examples that survived until the present day.
“There was a one-of-a-kind radiator that was really heavy, but it was super cool to be able to carry it with my hands and move it, knowing we found it here,” Senior Airman Mason Stutheit, a heavy equipment and pavement specialist with the engineering squadron, told Stars and Stripes in an interview Thursday.
Among the other artifacts were engine components, landing gear assemblies, airframe sections and deactivated munitions, according to the wing.
Several airmen were tasked with loading and preparing the artifacts for transport after control was transferred to local authorities.
“It’s crazy that they chose me out of all people, but it was really cool being able to handle a piece of history,” Airman Heriberto Gamboa, a heavy equipment and pavement specialist, said in an interview Thursday.