Japan will assemble and inspect AIM-120 missiles on its own soil, adding a Japanese line to the industrial base behind a missile Japan's defense minister called essential for the F-35. Japanese Defense Minister Shinjiro Koizumi announced on Oct. 28 that the two governments agreed to establish a final assembly and inspection facility for the Advanced Medium-Range Air-to-Air Missile in Japan, The War Zone reported. Koizumi made the announcement after meeting US Secretary of War Pete Hegseth on the sidelines of the ASEAN Defense Ministers' Meeting-Plus in Cebu, Philippines.
The facility falls under Operation Supercharge, a broader initiative to speed US-Japan cooperation on defense equipment and technology. Neither government has said where the plant will sit, when it will be built, how many missiles it will turn out or which Japanese company will run it.
"We finally reached an agreement on the establishment of a final assembly and inspection facility in Japan for the AMRAAM air-to-air missile, which is essential for the F-35," Koizumi said, according to a translation of his remarks published by Air & Space Forces Magazine.
What Koizumi and Hegseth Agreed in Cebu
Koizumi framed the deal as serving both supply and industry. "This is a groundbreaking agreement that will not only ensure the acquisition of equipment needed by both Japan and the United States, but will also strengthen Japan's defense industry base," he said, per the same translation.
Washington's account of the meeting was more reserved. The Pentagon readout did not mention the AMRAAM facility at all. Instead, it said Hegseth "welcomed Japan's efforts to strengthen its defense industrial capacity, and both leaders committed to continue close coordination on critical munitions production," Air & Space Forces Magazine reported.
The gap between the two readouts leaves the details on the Japanese side for now. Tokyo announced the agreement; Washington described the relationship around it.
AMRAAM was not the only missile on the table. Koizumi also confirmed that the two countries agreed to share technical information intended to raise production of the SM-3 Block IIA interceptor, a jointly developed ballistic missile defense round, according to The War Zone. Neither government has said how much the SM-3 arrangement is expected to increase output or when additional interceptors might arrive.
Why the AMRAAM Japan Facility Took More Than Two Years
The Cebu announcement closes a negotiation that started in 2024. A feasibility study supported by Mitsubishi Electric and Raytheon followed, and by April 2026 the discussions had widened to include possible Japanese production of circuit card assemblies in addition to final assembly and inspection, The War Zone reported.
Two obstacles slowed the process. The first is Japanese law and policy. Air & Space Forces Magazine noted that Japan has severe constitutional restrictions on exporting lethal weapons or coproducing offensive weaponry with allies, limits that date to its post-World War II foreign policy. The War Zone described the same longstanding restrictions as complicating arrangements involving weapons considered offensive in nature.
The second is security. The AMRAAM contains classified guidance systems and intellectual property that require safeguards to prevent leaks, according to Air & Space Forces Magazine. The War Zone drew a consequence for the plant's scope: the planned facility stops short of a commitment to manufacture the missile domestically, and a final assembly and inspection model lets Japan complete and check missiles using components produced through an industrial arrangement.
How the Plant Fits the 1,900-Missile Production Goal
The Japanese line arrives as the United States tries to sharply raise AMRAAM output. A February framework agreement calls for RTX to increase production "to at least 1,900" missiles per year, and the Japanese facility would account for a share of that overall target, The War Zone reported. A five-year RTX contract with two option years, valued at up to $20.7 billion, backs that ramp.
US and Japanese officials have said the agreement will diversify the AMRAAM industrial base and build regional stockpiles for the United States and its allies, according to Air & Space Forces Magazine. For Tokyo, domestic assembly could support replenishment of its own AMRAAM stocks. For Washington, The War Zone noted, another qualified production location diversifies the network serving US forces and international customers.
How much the plant adds to total output depends on numbers nobody has published: its eventual capacity and the division of manufacturing work between Japanese and US industry, The War Zone said.
RTX described its own preparations in a written statement. "We have invested heavily over the past several years to expand capacity, modernize manufacturing, and strengthen our supply chain," an RTX spokesman told Air & Space Forces Magazine. "RTX proactively sourced $80 million in test equipment before any award. These investments will ramp annual production over the coming years to at least 1,900 AMRAAM missiles."
The spokesman also pointed to the program's known chokepoints. AMRAAM production has faced bottlenecks from subcontractor component supply problems and solid rocket motor lag times, according to the magazine. "Like many advanced defense systems, AMRAAM relies on complex components that have long lead times," the spokesman wrote, adding that new US rocket motor production lines are coming online in 2027.
What the Japan Deal Leaves Unanswered
The open questions are concrete. The location, opening date, annual output and precise manufacturing responsibilities of the Japanese facility remain undisclosed, The War Zone reported. The SM-3 initiative also lacks a published production-growth target.
The supply chain question matters most. A final assembly and inspection site can only move as fast as the components it receives. If rocket motors and other long-lead components remain the limiting factor, a new assembly line in Japan adds a place to finish missiles without necessarily adding parts to finish them with. The 2027 rocket motor lines and the possible Japanese circuit card work discussed in April both bear directly on that constraint.
What It Means for Contractors
For the AMRAAM supplier base, the agreement points to a production network that will span two countries, with final assembly and inspection work flowing to a Japanese partner that has not yet been named. Mitsubishi Electric supported the earlier feasibility study, though neither government has identified the industrial partner for the plant.
US subcontractors that build AMRAAM components should expect their parts to feed more than one assembly location. That raises the stakes on the long-lead components RTX has already flagged, including rocket motors. If talks on Japanese circuit card assembly production advance, some electronics work could move into Japan's industrial base, a development US electronics suppliers will want to track.
The deal also signals how allied coproduction is likely to work for sensitive munitions: assembly and inspection abroad, with classified guidance technology and intellectual property protected by safeguards. Firms that handle export compliance, technology protection and international supply chain management for programs like AMRAAM and SM-3 Block IIA stand to see more of this work as Operation Supercharge expands. Companies should watch for the facility's location, partner and capacity announcements, which will define the actual scale of the opportunity.
