JS Kaga F-35B Takeoff and Landing Training Indicates a New Phase in Western Pacific Air Defense by 2026

What first caught my attention in the Japan Maritime Self-Defense Force's announcement was not the name of the training but the participating units. The materials from the Maritime Staff Office dated May 28 state that the IPD26 2nd Surface Unit's destroyer "Kaga" and the U.S. Marine Corps F-35B will conduct takeoff and landing training in the Western Pacific from June 4 to 12. Although it is just a one-page announcement, it indicates that Japan's carrier-like operations are transitioning from "testing" to "repeated training."

Combination of Kaga and F-35B

The "Kaga" is an Izumo-class destroyer with a standard displacement of approximately 19,500 tons and a full load of about 27,000 tons, with a length of about 248 meters. Since 2024, modifications have been made to the bow shape, heat-resistant deck, lighting, and compartments to prepare for the F-35B's short takeoff and vertical landing capabilities. It is also noteworthy that the counterpart is not the Air Self-Defense Force but U.S. Marine Corps aircraft. Japan is still in the stage of accumulating personnel, deck procedures, and maintenance flow for carrier operations, with the U.S. Marine Corps serving as instructors in this regard.

Not an Air Defense Ship, but a Maritime Air Base

The significance of this training is difficult to grasp through the old debate of whether Japan possesses an "aircraft carrier." The air bases in the southwestern islands are vulnerable to missile attacks in terms of runways, fuel, ammunition depots, and maintenance facilities. If F-35Bs can be dispersed at sea, it would not only maintain air superiority but also enhance rapid deployment to island areas, aerial surveillance of maritime traffic routes, and information sharing for anti-ship operations.

However, the "Kaga" is not a U.S. Navy amphibious assault ship or a large aircraft carrier. There are limitations in terms of the number of aircraft it can carry, ammunition resupply, maintenance capacity, and the coexistence of anti-submarine missions as a destroyer. Therefore, in my view, it is more accurate to see this ship as a mobile air node connecting the U.S. Marine Corps, Air Self-Defense Force, and Maritime Self-Defense Force rather than as a standalone strike ship.

Connection to the Japan-U.S. Defense Ministerial Meeting on May 30

During the Japan-U.S. defense ministerial meeting held in Singapore on May 30, forward presence in the southwestern region, more realistic training, and temporary deployment of U.S. missile systems were confirmed. Furthermore, Valiant Shield 2026 and Resolute Dragon 26 are scheduled for late June, and according to USNI News, Typhon and HIMARS are expected to be deployed to Kanoya Air Base and participate in integrated anti-ship training around Amami Oshima.

Viewing the training of the "Kaga" and F-35B in this context reveals a line rather than a point. The F-35Bs at sea, ground-based anti-ship missiles, integrated operational command, and dispersed units of the U.S. 7th Fleet and Marine Corps are all set to connect within the same operational space in the Western Pacific. During the Cold War, the JMSDF served as a shield supporting U.S. carrier strike groups. By 2026, the JMSDF aims to add a small but significant air capability to that shield.

Remaining Constraints

However, institutional distortions remain. The F-35B is an aircraft of the Air Self-Defense Force, while the ship is operated by the Maritime Self-Defense Force. Even if procedures are refined using U.S. Marine Corps aircraft, the ultimate question is whether the maintenance personnel, pilots of the Air Self-Defense Force, and deck personnel of the JMSDF can operate in sync. This is more challenging than the introduction of equipment.

What is being questioned on the deck of the "Kaga" is not the presence of carrier-based aircraft, but whether the Air Self-Defense Force and the Maritime Self-Defense Force can fight on the same clock.

References

• Maritime Staff Office "Japan-U.S. Bilateral Exercise" May 28, 2026
• Japan Ministry of Defense "Japan-U.S. Defense Ministerial Meeting" May 30, 2026
• Joint Staff Office "Participation in Valiant Shield 2026" May 22, 2026
• USNI News "Japan Announces 2 Major Western Pacific Exercises with U.S." May 25, 2026