Recently, multiple reports have emerged in the Japanese and international press suggesting a serious degree of interest within the Japanese Ministry of Defense in converting Japan’s Izumo-class helicopter destroyers—the largest ships serving in the Maritime Self-Defense Force today—into aircraft carriers. Should they be converted, the vessels would carry the F-35B, presumably. The U.S. Marine Corps variant of the U.S.-built fifth generation stealth fighter is capable of short take-off and vertical landing (STOVL) in a way that could be theoretically accommodated by the Izumo-class with modifications.
In late-December 2017, Kyodo News Agency and Reuters noted, citing Japanese Defense Ministry officials, that “Japan is considering refitting the Izumo helicopter carrier so that it can land U.S. Marines F-35B stealth fighters.” The Mainichi reported that this interest was more serious: “Within the Defense Ministry, there is even a proposal circulating to convert the Maritime Self-Defense Force (MSDF)’s Izumo helicopter carrier into a regular aircraft carrier.”
The idea of the Izumo-class being converted into a small aircraft carrier isn’t new and the Japanese government has long sought to avoid the perception that these vessels are, in fact, carriers. Under Japan’s Pacifist post-war constitution, successive Japanese governments have forbid the construction or import of any defense assets that could be considered primarily offensive, such as aircraft carriers.
Prime Minister Shinzo Abe’s government has started to test the limits of those limitations; in recent months, Japanese Defense Minister Itsunori Onodera has hinted at the possibility of Japan acquiring long-range conventional cruise missiles to potentially preempt North Korean ballistic missile launches. (This kind of capability could be reasonably interpreted to comply with Japan’s defensive obligations, proponents argue.)
Cruise missiles aside, the recent reports concerning a possible Izumo conversion are curious. The conversion of these vessels, while possible in theory, would be costly and negatively affect the MSDF’s ability to sustain anti-submarine warfare operations in the short-term. The lead ship of the class, JS Izumo, has also become something of a tool in signaling Japan’s expedition. It’s 2017 tour to Southeast Asia, the South China Sea, and the Indian Ocean was a rare display of Japanese naval presence across the broader Indo-Pacific.
The question that looms now is just what degree of seriousness lies behind the proposal to eventually convert the Izumo to allow for STOVL F-35B operations. For all one knows, the recent reports may be suggestive of a trial balloon by interested parties within the Japanese Ministry of Defense, who have strategically approached the press to gauge the reactions of various parties. It’s important too to not make too much of these reports; proposals, if they exist, can end up on the bureaucratic trash-heap. While the allure for a carrier conversion may exist for some in the Japanese Defense Ministry, there are plenty of good reasons to keep the Izumo-class as is. Either way, the Izumo‘s fate may be one to watch in 2018.