Two Marine Corps F-35B Lighting II Joint Strike Fighters took off and landed on Japan’s largest warship, JS Izumo (DDH-183), on Oct.3, marking the first time that fixed-wing aircraft have operated off a Japanese warship since World War II.

Since November 2018, the Japanese government has also announced a plan to upgrade two Izumo-class helicopter destroyers to turn them into mini-carriers carrying more than 12 F-35 stealth fighters.

“Ever since we got these ships ( Izumo-class multipurpose destroyer, built in 2015), we’ve wanted to use them for many purposes,” Japanese Defense Minister Takeshi Iwaya told reporters.

Although, the Izumo-class warships are considered to be quite small for fixed-wing aircraft to operate. It is worrisome that Japan has not operated a fixed-wing aircraft on board ships since World War II and needs to train pilots, deck crews, and maintenance crews to handle the unique challenges of operating an aircraft carrier.

And according to Japan’s post-World War II constitution, it is forbidden to engage in aggressive military activities. For decades, Japanese leaders have interpreted this prohibition that it means legally, the Japanese Navy is not allowed to own an aircraft carrier.

The Japanese Navy, therefore to circumvent the ban by purchasing what it calls a “helicopter destroyer,” which is a type of surface ship with an aircraft hangar with a wide deck for helicopters and fixed-wing to take off and land.

This time, the Izumo has been modified by Japan to allow the F-35B to operate. This activity will set the stage for Japan to deploy its F-35B aircraft onboard the Izumo in the next few years. The F-35B is capable of short take-offs and vertical landings. The October 3 deployment is believed to be the first to have a fixed-action fighter aboard a Japanese warship since World War II.

The modification of Izumo and Kaga are paired with a planned JSDF buy of 42 F-35Bs to operate from the two ships. The first of the JSDF F-35Bs are set to arrive in FY 2023 and Marine F-35s are expected to continue operating off the two ships as Japan acclimates itself to using the fighters. The JMSDF has already conducted a series of engagements and exchanges in relation to F-35B operations with the U.K. Carrier Strike Group 21 (CSG21) while it was in Japan in early September

The Izumo is 248m long, 38m wide, and has a displacement of 27,000 tons at full load. Izumo’s speed can reach more than 30 knots, carrying up to 28 aircraft.

Currently, this “helicopter destroyer” Izumo is at the port of Iwakuni in Yamaguchi Prefecture, where there is an airfield that houses the aviation unit of the US Marines and US Navy squadrons.

The deck of the Izumo has just been upgraded with heat protection this summer at the port of Isogo in Yokohama, allowing F-35Bs to land vertically on board.

The entire renovation of the Izumo class is expected to be completed by 2026. The second ship in this class, the Kaga, is undergoing a similar modification.

Japan plans to buy 157 F-35 aircraft, including 42 F-35Bs. Contracts have been signed for the first eight, of which four will be delivered in fiscal 2024. Funds for the remaining four have been included in the budget proposal for fiscal 2022.

And now, Japan’s Izumo ship, after being improved, can be seen as a small aircraft carrier, not a “helicopter destroyer” as before.