Japan is reassembling its carrier fleet, a feat that has n’t been done since World War II ended. This job involves substantial modifications to its Izumo- group “helicopter destroyers”, transforming them into F- 35B lighting carriers, a development that is quickly gaining momentum.  ,
This quarter, Naval News reported , that the Japan Maritime Self- Defence Force ( JMSDF) had completed the initial two- phase changes for its helicopter destroyer JS Kaga to perform the , Lockheed Martin , F- 35B fighter aircraft. According to Naval News, the first adaptation was carried out over a regular assessment for about two centuries, beginning at the end of the fiscal year 2021. The publication next adds that the benefits of those tests will be reflected in the next special modification of Izumo, which may begin this fiscal year.  ,
Naval News reports that the JMSDF will continue to make the necessary modifications to make the F-35B operationally capable on destroyers of the Izumo-class obsolete.
The meticulous planning of the modifications to two Izumo- class helicopter destroyers, JS Izumo and JS Kaga, underscores the JMSDF’s strategic foresight and capability. These modifications are strategically being made in two main stages, demonstrating the accuracy of the JMSDF’s timing, which coincides with the vessels ‘ regular refit and overhaul initiatives, which take place every five years. Around the fiscal year 2027, both ships are expected to convert to F-35B light carriers, further instilling confidence in the JMSDF’s capabilities and strategic planning.  ,
According to Naval News, the JMSDF has already started the conversion of JS Izumo into a carrier that can support F-35B operations in Yokohama City of Kanagawa in the first half of 2020. Further, it further states that the second Izumo refurbishment will begin in 2024, with the Japanese Ministry of Defense anticipating that the modifications will be finished by the end of the fiscal year 2026. This ongoing improvement makes the JMSDF’s potential future capabilities more ephemeral.
The Izumo- class helicopter destroyers ‘ conversion into light carriers has been the subject of much controversy. Critics point out that it conflicts with Japan’s long-standing pacifist foreign policy. However, other criticisms of Japan’s decision to rearm with light carriers come from a military perspective.  ,
Brendon Cannon and Ash Rossiter argue that while the JS Izumo and JS Kaga helicopter destroyers ‘ conversions to light carriers have tangible military advantages, such as strengthening Japan’s territorial defense capabilities, they do not fully support the decision to convert them.  ,
Cannon and Rossiter point out from a military standpoint that China’s and North Korea’s increasingly capable anti- access/area- denial capabilities ( A2/AD ) make carriers especially vulnerable. They add that Japan lacks the necessary screening and logistics ships to support carrier operations and that the challenging infrastructure, technology, knowledge requirements, and system integration challenges mean that, in the near future, Japan wo n’t have independent carrier warfare capabilities.
However, Cannon and Rossiter suggest a more optimistic perspective. They suggest that it might be more advantageous for Japan to run light carriers for a larger US-led coalition.  ,
In line with that perspective, Japan’s light carriers can address a looming US” carrier gap” that could leave it with insufficient carriers for effective operations. This potential for cooperation and shared defense responsibilities could strengthen Japan’s strategic standing and military stance.
Bryan McGrath asserts in a March 2024 Defense One article that the delay of the next Gerald R. Ford supercarrier to 2029 would further deteriorate the US naval shipbuilding base, cause labor shortages, and have an impact on the US nuclear submarine industrial base because both share important technologies like nuclear propulsion.  ,
According to McGrath, long production gaps will shrink the US Navy’s 11 already overstretched carriers, observing the guaranteed lifespan of their nuclear cores, and that the US Navy can only keep two of the best three carriers forward deployed indefinitely.
Given that,  , multinational naval exercises , involving the US and Japan’s JS Izumo and JS Kaga may offer a glimpse of the role of Japan’s light carriers in a coalition setting.  ,
However,  , in an October 2021 War on the Rocks article, John Bradford and Olli Pekka Suorsa note that light carriers are unlikely to change the anticipated outcomes of combat scenarios envisioned in the Korean Peninsula, Senkaku Islands, the Taiwan Strait, and the South China Sea.
According to Bradford and Suorsa, light carriers are still expensive assets that are vulnerable to more sophisticated anti-ship missiles and submarines. They claim that it is unlikely that they will change how much naval supremacy is distributed, which affects deterrence calculations. They claim that light carriers offer less of a return on investment than long-range land-based aircraft and more geographically distributed base options.  ,
In addition, Bradford and Suorsa claim that if Japan engages in a conflict in the South China Sea, its light carriers could encounter China’s A2/AD capabilities, which would put them at an unnecessary risk.  ,
Although there are strong arguments in favor and against of Japan’s light carriers ‘ military value, Cannon and Rossiter contend that their true worth may lie in their symbolic value, which helps Japan’s credibility in the Pacific and with the US, respectively.  ,
Yoshihiro Inaba writes in a letter from April 2022 Naval News that Yoshihiro Inaba believes that JS Kaga’s conversion is intended to strengthen Japan’s Indo-Pacific presence during the Indo-Pacific Deployments ( IPD), which are long-term deployments of the Izumo-class ships and other ships in the region, which have been ongoing for a number of years.  ,
As the F- 35B is the main asset of Japan’s light carriers, and the country is one of the largest F- 35 operators, the type could enhance , interoperability with US and allied forces , and facilitate further technology transfer between Japan, the US and its other key allies.
The F- 35B could also be a focal point of Japan’s participation in AUKUS Pillar II, which focuses on advanced technologies, in contrast to AUKUS Pillar I, which focuses on acquiring nuclear attack submarines ( SSN) for Australia.  ,
Breaking Defense made it clear that AUKUS is considering cooperating with Japan on AUKUS Pillar II advanced capability projects, but that actual AUKUS membership for Japan is off the table.
Such projects under AUKUS Pillar II include AI, quantum computing, undersea drones, hypersonic missiles and electronic warfare technologies. Japan’s F- 35Bs may benefit from advancements in AI for sensor fusion and electronic warfare technology for radar warning, targeting support, and self- defense.  ,