Major change is afoot in Ichigaya, the Tokyo neighborhood that contains the Japanese Ministry of Defense, in recent weeks; or at least media reporting would suggest as much. In the days after Defense Minister Itsunori Onodera announced that MOD would for the first time pursue the purchase of long-range cruise missiles, a series of reports emerged stating that Japan is considering converting its Izumo-class helicopter destroyers into aircraft carriers and that the Air Self-Defense Force is pondering the introduction of electronic warfare aircraft into its fleet. In response to these reports, the Chinese admonished Japan to be mindful of history, while media outlets have assembled panels asking if Japanese “pacifism” is under fresh attack.
This cycle has become routine, if unsurprising. From a layman’s perspective, a shiny new missile or a hulking warship is a far clearer manifestation of change than an obscure defense planning document winding its way through the bureaucracy. Where this approach becomes problematic, however, is in confusing which of the two – systems or doctrine – takes analytical priority in dissecting how and why the SDF is changing. In a perfect illustration of how this can lead to a “tail wagging the dog” phenomenon, some commentators have suggested that MOD’s plan to convert the Izumo into an aircraft carrier is, in and of itself, a distinct violation of Japan’s “defensive defense” policy. Discounting the fact that the conversion idea is still merely a proposal, viewing a weapons system itself as the driver of a broader doctrine or strategy is flawed logic. Weapons are merely the tools by which militaries achieve their tactical and operational objectives. Criticizing acquisition of a particular weapon while overlooking how, when and why it might be used misunderstands the relationship between systems and doctrine.
Criticizing acquisition of a particular weapon while overlooking how, when and why it might be used misunderstands the relationship between systems and doctrine
Further, because doctrinal items like “defensive defense” and “war potential” exist in relative rather than absolute terms, the nature of “defensive defense” and “war potential” have always been defined in comparison to the power of Japan’s potential adversaries. Historically, this phenomenon led opposition politicians in the late 1960s to demand that the ASDF remove mid-air refueling functionality from its newly purchased F-4 Phantom fighters. With Japan’s main adversaries at the time fielding military forces incapable of projecting power far from shore, in-air refueling capability was looked upon as an unconstitutional means of extending the reach of Japanese combat forces. In the decades since, as the regional security environment has shifted, mid-air refueling has become an integral aspect of ASDF operations. Drawing a line in the sand regarding acquisition of particular weapons systems, rather than debating doctrine or strategy, risks misunderstanding that the SDF’s capabilities have always been defined relative to the power of its potential adversaries.
The frame of reference, then, should not be the move from a helicopter destroyer to an aircraft carrier, or from cruise missiles of a given range to longer-ranged models, but rather major doctrinal shifts embodied in changes to the National Defense Program Outline (NDPO) over the past thirty years. In turn, these doctrinal shifts inform decisions on the systems Japan decides to purchase through the Mid-Term Defense Program (MTDP). By understanding these doctrinal shifts in the context of the operations the SDF must prosecute in relation to its adversaries, one may have a firmer grasp on how the force will change. With revision to Article 9 a major possibility in the coming year, properly understanding the relationship between doctrine, adversary capabilities, and systems is critical.
By understanding these doctrinal shifts in the context of the operations the SDF must prosecute in relation to its adversaries, one may have a firmer grasp on how the force will change
In particular, the most significant doctrinal shift underpinning changes to the SDF has been the movement from a “Basic Defense Force” (BDF) to a “Dynamic Defense Force.” (DDF). Embodied in the 2010 NDPO compiled by the DPJ government, the DDF concept (and its successor in the 2013 NDPO, the “Joint DDF”) was a decisive shift away from the static defense doctrine of the BDF. With major threats to the west (the challenge posed by North Korean missile forces) and south (China’s repeated incursions into the maritime contiguous zone of the Senkaku islands), Japanese defense planners envisioned the SDF undertaking entirely different military operations under the DDF doctrine when compared to those fulfilled by the BDF. The BDF plan envisioned a static defense of Hokkaido with heavy armor units – a high of 12 divisions operating 1200 main battle tanks under the 1976 NDPO – tasked with destroying Soviet invasion forces as they landed on the beaches. With the Chinese and North Korean militaries still incapable of power projection, there was little reason to fear seizure of one of Japan’s far-flung southwestern islands or a sudden missile attack on the main islands themselves.
But with the rise of the DPRK missile threat and Chinese naval designs on the East and South China Seas (ECS and SCS), Japanese strategists saw the required defensive perimeter pushed hundreds (if not thousands) of miles away from the main islands. To defend against these threats, the SDF would need to project power to deny adversary powers access to crucial maritime chokepoints and defeat invasion attempts, embrace amphibious and aerial lift capabilities to “swing” units from one theater to another, and develop the capability to destroy adversary ballistic missiles either in flight or on the ground. The Joint DDF doctrine in turn emphasized the need for the GSDF, ASDF, and MSDF to speak with one another and operate together cohesively. While much work remains to be done, the seeds were planted for Japan’s first “marine” brigade of GSDF soldiers fielded on MSDF ships.
The equipment that Japan has introduced in recent years has been for the sake of fulfilling each of these operational requirements. By design, these procurement decisions have mirrored decisions taken by adversary nations. North Korean moves to obscure ballistic missile operations through the use of transporter erector launchers (TELs) and nighttime operations have necessitated the procurement of more sophisticated intelligence, surveillance, and reconnaissance (ISR) equipment to track them, while the ever-increasing range of Chinese missile forces has given rise to a Japanese stand-off missile capability to defeat invasion attempts outside of the threat envelope of PLA “anti-access/area-denial” weapons. The rumored possibility of Japanese short/vertical takeoff or landing (SVTOL) aircraft and aircraft carriers are, in turn, designed to counter PLA rocket force doctrine designed to crater runways and destroy other air control facilities. One can imagine that MOD would not wish to relinquish air dominance in the southwest islands at the hands of Chinese runway fragmentation efforts, and so SVTOL aircraft (and carriers) can enable rapid sortie generation from unimproved or otherwise ad-hoc airfields.
It is important to note that none of the above-mentioned procurement decisions or doctrinal shifts directly challenge the foundational notion of “defensive defense.” The Joint DDF doctrine and its reliance on interoperability, mobility, and power projection explicitly envisions the usage of power projection forces for the defense of Japanese territory. While Japan is heavily involved in the South China Sea dispute through its various capacity building programs and is taking a larger role in Indian Ocean naval diplomacy, nothing in MOD’s official doctrine suggests the use of kinetic force in either location. While there is currently a robust debate among the Japanese commentariat on the wisdom of adopting a so-called “strike enemy bases capability” (teki kichi kogeki noryoku), even proponents of this mission are suggesting that it would stick to the minimum use of force necessary and would occur after a first strike on Japanese forces or Japanese territory. With Japan continuing to forswear the possession of long-range weapons of mass destruction like strategic bombers or intercontinental ballistic missiles, there is zero evidence to suggest that the procurement of new weapons systems or munitions of increasing range represents a fundamental shift in the defensive defense doctrine.
There is zero evidence to suggest that the procurement of new weapons systems or munitions of increasing range represents a fundamental shift in the defensive defense doctrine
However, the strategic dynamics underpinning the move from the BDF to the Joint DDF suggest that the range and capabilities of the SDF will continue to increase, even if amendment to Article 9 fails to clear the Diet or a national referendum. North Korea continues to increase the operational sophistication of its missile force, introducing tactical innovations like “shoot and scoot” tactics for its TELs, launching from previously unknown locations, and firing missiles in waves steadily hedging against the declining influence and reach of its superpower ally, the United States. As MOD has been able to design a Joint DDF under the current legal framework, even if an Article 9 amendment proposal were to be defeated, the government could continue to increase the reach and capability of the SDF under this doctrinal framework.
In short, Japan’s forces will decrease in total troop strength but increase in size and reach, particularly among power projection forces and their associated logistical support units. While over the long term Japanese strategists continue to debate whether Japan should take an even more active role in the SCS and Indian Ocean given fears over Chinese domination of these valuable sea lanes, or whether Japan should tighten its security relationship with Taiwan, none of these fundamental shifts have yet altered the foundations of defensive defense. The true story of changes to the SDF, then, won’t be found on the shop floor of Mitsubishi Heavy, but rather the annals of MOD’s strategic planning offices.
Ben Rimland is a program assistant in the Asia program at The German Marshall Fund, where he researches Asia defense issues and coordinates programming and convening on the U.S.-EU-Asia relationship. Previously, he was based at the Inter-University Center for Japanese Language Studies in Yokohama. A graduate of both Columbia University (cum laude) and St. Antony's College, University of Oxford (MPhil, modern Japanese studies), his work focuses on the US-Japan alliance, Japan's security posture in Southeast Asia, and the Japanese foreign policy bureaucracy. He is concurrently a young leader at Pacific Forum CSIS.
