The Japan Maritime Self-Defense Force and US Navy simulate a beach-front assault at Camp Pendleton in California. Photo: Kenan O'Connor / US Navy

April 1 is rapidly approaching, and – jokes aside – this is when Japan’s first Amphibious Rapid Deployment Brigade (ARDB) is supposed to be in place and ready for any attempt by an enemy to seize Japanese islands. The new unit adds a fast, light, deployable capability to Tokyo’s growing portfolio of military assets.

The ARDB is not officially a marine corps: it is part of the Japan Ground Self Defense Forces’ Western Army Infantry Regiment, and will number well over 3,000. Although its size makes it similar to the UK’s well-regarded Royal Marine Commando Brigade, its training is American.

Starting in mid-January, 350 members of the ARDB spent a month in California, where they participated in maneuvers and warfare scenarios with US Marines – their mortal enemies in many a savage struggle in the 1941-45 Pacific campaign – as part of the Iron Fist 2018 exercises. They engaged twice in similar exercises in California in 2017. Japanese participation in Iron Fist exercises began back in 2006, athough formal planning for the creation of the ARDB did not get underway until after Prime Minister Abe took office in 2012.

The gear, too, is American. However a shortage of related equipment –notably MV-22B Osprey tiltrotor aircraft and AAV-7 amphibious assault vehicles – will limit the ARDB’s responsiveness until it is received.

During his testimony on March 15 before the US Senate Armed Services Committee, US Navy Admiral Harry Harris Jr., Commander of the US Pacific Command, spoke about the reason why the ARDB is so vital to Japan’s overall defense posture. He said:

“Tensions between Japan and China over the Senkaku Islands have largely stabilized since last year, but there is no long-term resolution in sight… China persistently challenges Japan’s administration over the islands by sailing Coast Guard ships near the Senkaku Islands and protesting Japanese reconnaissance flights. Chinese exercises prominently feature military actions focused on the Senkaku Islands, including exercises training for a possible future physical occupation of the islands and establishment of a maritime blockade to isolate the disputed areas. Clearly describing Beijing’s intent to the US and Japan, Chinese media prominently features stories that highlight those specific capabilities and actions. America’s policy is clear and has not wavered: the Senkaku Islands are under the administration of Japan and, as such, are covered by Article 5 of the US-Japan Treaty of Mutual Cooperation and Security. The United States opposes any unilateral action that seeks to undermine Japan’s administration of these islands.”

Japan creeps toward expeditionary capability – but no controversy at home

The ARDB is appearing as Tokyo lays the groundwork for a revision of Article 9 in the Japanese Constitution which, at present, greatly impedes Japan’s armed forces from taking on any offensive characteristics. Japanese voters have indicated recently and in the past that any revisions to Article 9 represent a very delicate undertaking and voter approval is by no means automatic.

But while polls have highlighted a lukewarm attitude toward the constitutional revision, the new unit is not controversial, according to one expert.

“China and Korea would most likely be those neighbors who would not view the formation of the ARDB kindly, for obvious historical and contemporary interstate rivalry reasons”

“The ARDB plan has already been in the works for some time, and the Japanese public does indeed recognize the increasingly acute and complex security environment, especially challenges posed by not just North Korea, but also China in the East China Sea,” said Dr Swee Lean Collin Koh, a research fellow with the Maritime Security Program at the S Rajaratnam School of International Studies at Nanyang Technological University in Singapore, via email. “I believe this threat perception will still outweigh any potential repercussions in rolling out the ARDB in April.”

Opposition will probably be minor. “So far, we’ve not seen any Japanese public outcry following recent reporting about the aircraft carrier potential of the JMSDF’s Izumo-class helicopter destroyer [and] a somewhat similar type of Japanese response towards the ARDB could be expected,” said Koh. “However, we also will expect the Japanese opposition and activist groups to raise the issue, though I don’t think this would sufficiently gain momentum in mobilizing widespread shift in public opinion towards a more robust defense posture.”

William Brooks, adjunct professor of Japan Studies at the Johns Hopkins School of Advanced International Studies in Washington, concurs with Koh. “Since it is designed to protect the exposed southern flank, hundreds of small, remote islands, it seems likely that the public views the development of such a capability as a positive step in the defense of Japan,” said Brooks. “It will not likely get swept up in the debate over changing Article 9.”

Japan’s armed forces get more deployable

A marine unit is a critical component of any armed force with expeditionary ambitions. “It does demonstrate that Japan is gradually filling in the gaps in its defense armor,” said Brooks. “That capability must be looked at in the context of all of the other changes in the roles and missions of the SDF under the new defense cooperation guidelines with the US – and the equipment that is gradually being acquired to accomplish them.”

One issue is the modest size of the brigade. Brooks describes the ARDB as no match for China’s mammoth amphibious forces. “Japan would still need to heavily rely on the US Navy and Marines stationed in Japan to balance out…. Its existence, though, adds somewhat to the deterrent capability of the US-Japan Alliance,” said Brooks. “The new brigade, when it is up to full size, could in theory take back one of Japan’s remote islands if it is invaded by a foreign force. In reality, the chance that that capability would ever be used is quite low.”

Koh described the ARDB as key to the maturation and development of the Japanese armed forces. “The ARDB is supposed to be ‘self-contained,’ having better organic mobility and firepower capabilities,” the Singaporean academic said.

Even so, the new unit will need firepower, protection, sealift, airmobile and logistical support from the air and naval components of the SDF, which raises further questions. Koh describes “overcoming inter-service rivalries and (the promotion of) better force integration between them (as) the bigger challenge.”

What will the neighbors think?

Japan’s neighbors are monitoring the rise of Tokyo’s expeditionary units – notably, the ARDB and its controversial helicopter destroyers, which are, in effect, baby aircraft carriers. “China and Korea would most likely be those neighbors who would not view the formation of the ARDB kindly, for obvious historical and contemporary interstate rivalry reasons,” Koh said. “However, China would certainly view this ARDB roll-out as Japan’s attempt to ‘remilitarize’ and this would then feed ammunition for the PLA’s own ramping up of activities and bolstering of forces in the vicinity of the East China Sea.”

Even so, Brooks does not anticipate a strong Chinese reaction. “China knows of the unit’s existence and capability,” Brooks said. “I would be surprised if Beijing reacts strongly to something it has long ago factored into its strategic thinking.”

The activation of the force might also raise eyebrows in Moscow. Russia, because of the outstanding Kurils/Northern Territories dispute with Japan, would “also take this development as a justification for bolstering its already ongoing buildup on the occupied islands,” Koh said.

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