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The Return of Japanese Marines

Japan went without a dedicated amphibious force since World War II – until last weekend.

|April 10, 2018

By Phillip Orchard

More than 80 years ago, Japan unleashed one of the finest amphibious fighting forces in history, going toe to toe with the Americans in the Pacific and very nearly prevailing. But the country had gone without a dedicated amphibious force in the decades since – until last weekend. On April 7, Japan activated its first marine unit since World War II. Some 2,100 troops are being shifted to what will be known as the Amphibious Rapid Deployment Brigade, based out of the southern port city of Sasebo (conveniently, the new home port of the USS Wasp amphibious assault ship) and tasked with defending Japan’s remote southeastern islands. The move is just part of the largest overhaul of the Japan Ground Self-Defense Force since its founding in 1954.

That Japan – a country of 6,852 islands in a perpetually hostile neighborhood and utterly dependent on open sea lanes – allowed its amphibious capabilities to decay in the first place sheds light on the way that legal, political and budgetary constraints can hinder Japanese efforts to face up to burgeoning maritime security challenges on its doorstep. These aren’t going away, complicating Japan’s resurgence as a dominant military power in the Western Pacific. But Japan has always found ways to adapt when compelled to do so by outside forces. The revival of the Japanese marines merely underscores the weight of the concerns driving the country to reinvent itself again today.

Toeing the Line on Article 9

The erosion of Japan’s amphibious capabilities is, in large part, a legacy of World War II. Article 9 of Japan’s pacifist constitution – which the occupying Americans imposed on Japan, but which the country has generally embraced ever since – prohibits the use of military force for offensive purposes and effectively requires that any weapons acquired or developed by the military must be intended for defensive purposes. Article 9 hasn’t stopped Tokyo from building up considerable military firepower; the Japanese Self-Defense Force has superb defensive capabilities. But the law and accompanying political sensitivities, plus varying degrees of pressure from the U.S., have deterred the government from pursuing offensive weaponry such as long-range bombers or missiles, aircraft carriers and so forth.

Amphibious forces have generally been tagged as offensive, the rationale among Japanese pacifists being that their primary value would come in the sort of invasion that Tokyo had sworn off. But this label was hardly self-evident or binding. If the military had considered amphibious capabilities a priority, it likely could have worked to soften public opposition or find ways to sidestep it altogether. After all, Japan’s outer islands have always been vulnerable to seizure by hostile forces, not to mention natural disasters. (The military proved ill-prepared to respond to damage wrought by the 2011 Tohoku earthquake on remote islands, for example, helping generate political momentum for the revival of the marines.) Moreover, Japan has routinely toed the line on Article 9 with “defensive capabilities” that could certainly be used to wage war abroad. It has long maintained sophisticated fleets of fighter jets and attack submarines, for example. More recently, it launched a new class of flat-decked helicopter carriers that could serve as prototypes for a bluewater aircraft carrier. The line between offensive and defensive could be blurred when the military found it necessary to do so.

But Japan’s military buildup during the latter half of the 20th century took place amid tight budgetary and political constraints. There was only so much political and fiscal capital to go around, and Japan was reluctant to defy public opposition to capabilities that much of the military considered lesser priorities. Allowing capabilities such as amphibious warfare to languish was tolerable so long as Tokyo could rely on the U.S. to fill in the gaps. As a result, Japanese Self-Defense Force resources were devoted overwhelmingly to its main strategic priority – deterring a Soviet invasion of Japan’s main islands from the north – at a time when vital sea lanes to Japan’s south faced little threat. (An indigenous amphibious force was not considered vital to these war plans.) It just so happened that this was the Americans’ top priority as well. This meant the advocates of an amphibious force within the JSDF lacked the bureaucratic and public backing to shift the country’s strategic focus south and toward amphibious capabilities until well after the threat of Soviet invasion had evaporated. Japan had some of the assets needed for amphibious warfare, but momentum toward filling in the shortfalls and developing operational know-how – say, via joint training with U.S. Marines – didn’t begin to pick up until the past decade or so, particularly since the 2011 earthquake.

Japan is certainly still feeling the heat from the north and in the Sea of Japan. Just seven months have passed since North Korea last test-launched a ballistic missile over Hokkaido, after all. Moreover, Russia has been stirring tension over the Kuril Islands, for example by landing fighter jets on the disputed isles last month, staging exercises nearby, and generally stonewalling Tokyo’s efforts to forge a diplomatic solution. (Japan and Russia have never signed a World War II peace treaty because of the Kurils dispute.) But Japan’s strategic priorities are clearly moving south, owing overwhelmingly to China’s rapid military modernization, uncertainties about U.S. treaty commitments, and Japan’s enduring core imperative of deterring threats to indispensable import routes. As a result, Tokyo has found ways to shrug off the internal constraints on amphibious development that weren’t considered effectively insurmountable before.

Confronting a New Reality

The center of gravity of Japanese military planning is settling firmly over the East China Sea, particularly a string of uninhabited but hotly contested islands known in Japan as the Senkakus (called the Diaoyus in China). Located just over 100 miles (160 kilometers) northeast of Taiwan, the Senkakus may be where Chinese and Japanese geopolitical imperatives intersect most directly. Japan controls the Senkakus, but it has good reason to think China cannot abide this status quo. This is, in large part, because of China’s own dependency on the free flow of imported raw materials and exported goods. The Senkakus make up a small but important part of what’s known as the first island chain, stretching from Japan to Indonesia. Should a foreign navy (read: Japan or the U.S.) use this chain to block Chinese access to the Pacific or Indian Ocean basin, China would descend into economic and political chaos. Thus, China needs to push outward, whether by force or by striking a political arrangement with a foreign government like the Philippines, to blow a hole in any line of containment set up by the U.S. and its allies.


(click to enlarge)

The Senkakus themselves have only limited military value – far less than Okinawa, for example, 250 miles to the northeast. The same is true of China’s artificial islands in the South China Sea. But they could certainly host the sorts of surveillance and radar installations; missile defense, anti-ship and anti-aircraft emplacements; or network of seabed sensors that would restrict the Chinese navy’s ability to operate in its littoral waters. Inversely, installing its own assets on the Senkakus would bolster China’s own anti-access/area denial capabilities and complicate U.S. operations in the region – or perhaps even frustrate U.S. efforts to come to Taiwan’s aid in the event of a Chinese attempt to retake its prodigal province. Moreover, operating freely in the East China Sea is critical to Chinese nuclear deterrence. China needs long-range submarine-launched ballistic missiles to ensure a second-strike capability against other nuclear powers. But submarine warfare is perhaps China’s biggest naval weakness, with both Japan and the U.S. having substantial technological superiority, not to mention decades more real world operational experience.

Taking the Senkakus wouldn’t eliminate China’s shortcomings here, but it would make it riskier for the Japanese or U.S. to deploy air and surface fleet assets in support of anti-submarine warfare operations. This becomes particularly important with longer-range Chinese submarine-launched ballistic missiles coming online, allowing China greater second-strike assurance even if Chinese subs can’t yet evade their Japanese and U.S. counterparts in waters farther from Chinese shores. (Again, the same is true of China’s artificial islands in the South China Sea.)

In other words, China’s need to one day seize the islands is clear. Indeed, China hasn’t exactly been shy about its intentions. It declared an air defense identification zone over the Senkakus in 2013, and Japanese warplanes were scrambled to intercept incursions into Japanese airspace (mostly by Chinese aircraft) a record 1,168 times in 2016. Chinese fishing fleets (which would be used as a maritime militia in a conflict) and coast guard vessels (the largest of which are basically lightly armed frigates) have become regular visitors to the islands. In January, a new Chinese nuclear submarine surfaced alongside a frigate just off the Senkakus. Thus, Japan’s need for an amphibious force equipped to retake them is likewise becoming abundantly clear.

For Japan, the issue centers on the country’s fundamental and enduring weakness: Its near-total dependence on commodity imports, particularly those arriving from the Middle East and Southeast Asia through oft-contested waters. Japan has an extraordinary dearth of natural resources. If China or another hostile power were to use islands like the Senkakus or those in the South China Sea to sever this lifeline, Japan’s economy would wither on the vine. Japan’s grand strategy has revolved around this vulnerability ever since it industrialized in the late 1800s. It drove Japan’s imperial expansion into China and Southeast Asia in the 1930s-1940s, and it sparked the war in the Pacific shortly thereafter, with U.S. threats to Japanese oil supplies leading to the attack on Pearl Harbor. For decades afterward, U.S. security guarantees and China’s weakness allowed Japan to focus elsewhere. But such a posture was never going to be permanent. Even if warily, Japan is facing up to its uneasy geopolitical reality.