A Self-Defense Forces unit dubbed “Japan’s Marine Corps” made headlines this week when details were revealed of an alleged secret 2015 pact with the U.S. over stationing the amphibious troops at Camp Schwab in Okinawa’s Henoko District.

Tokyo strongly denies the report, but that allegation and China’s growing maritime assertiveness have cast a spotlight on the Amphibious Rapid Deployment Brigade, the first responders in any future conflict surrounding the nation’s outer islands.

What is the brigade and what is it for?

The Amphibious Rapid Deployment Brigade was established in March 2018, under the Ground Self-Defense Force. It was set up to respond to security situations that require faster mobilization of land, sea, and air forces at a national level than had been traditionally available.

The brigade was established with 2,100 personnel — that includes the Western Army Infantry Regiment, which was established in 2002 for the purpose of specializing in amphibious operations.The brigade’s primary duty is to secure any islands that have been illegally occupied.

For Japan, that is a particularly large task. As retired GSDF Lt. Gen. Koichiro Bansho noted in a 2018 Japanese government-sponsored study by the RAND Corp. on meeting the challenge of amphibious operations, the nation has about 30,000 kilometers of coastline around a total of nearly 6,900 islands that it must defend. This figure includes 2,852 remote islands, of which nearly 2,700 are uninhabited.

While these remote islands stretch from Hokkaido to Okinawa, many are located either to the southwest of Kagoshima Prefecture or the main island of Okinawa. Japan’s most southwesterly island, Yonaguni, is within sight of Taiwan and roughly 150 kilometers from the Senkaku Islands, the subject of a territorial dispute between Japan and China. The brigade is part of a larger strategy by the GSDF to strengthen its presence through the Nansei Shoto region (southwest of Kyushu) in order to protect Japanese territory from Chinese provocations.

Where is the brigade located and what does it include?

The brigade’s headquarters is at Camp Ainoura, near Sasebo, Nagasaki Prefecture, where the Maritime Self-Defense Force and the U.S. Navy have bases. Parts of the brigade are also currently stationed at Camp Sakibe (Nagasaki Prefecture) and at two other camps (Kusu and Yufuin) in Oita Prefecture.

It consists of two amphibious regiments, an assault battalion with AAV-7 amphibious assault vehicles designed for beach landing troops, an artillery battalion, a reconnaissance company, a signal company, an engineer company and a logistics support battalion.

The Senkaku Islands, the subject of a territorial dispute between Japan and China, in Okinawa Prefecture | KYODO
The Senkaku Islands, the subject of a territorial dispute between Japan and China, in Okinawa Prefecture | KYODO

Is the brigade equivalent to a Japanese version of the U.S. Marines?

There are some similarities in operational roles for their respective nations. The Japanese brigade’s objective, as outlined by the Defense Ministry in 2013, is “to land, recapture and secure without delay any remote islands that might be invaded.” They would be the first on such an island, with regular GSDF, MSDF and Air Self-Defense forces arriving afterward.

This is identical to some of the core roles that the U.S. Marines are expected to perform for the U.S. However, unlike the U.S. Marines, Japan’s amphibious brigade is not an expeditionary force. This means its purpose is only to defend Japanese territory, not to be dispatched to other countries. The government might send it to other countries for humanitarian assistance and disaster relief, but not for offensive purposes.

More fundamentally, the U.S. Marines are able to conduct operations on land, sea and air with their own assets, while the amphibious brigade will have to work closely with the MSDF and the ASDF to be effective in all three domains.

Is there cooperation between the U.S. military and the brigade?

Mutual training exercises between brigade personnel and the U.S. military are now taking place on a regular basis. In January and February 2020, for the first time, a brigade regiment participated with the U.S. Marines, in a training exercise in California called Iron Fist 2020.

In November, another training exercise, Keen Sword, involving U.S. Marines and brigade troops took place on Gajajima, an abandoned island that is part of Kagoshima Prefecture.

The simulation featured U.S. and Japanese troops landing simultaneously on a remote island occupied by enemy forces. It included seizing territory threatened by the enemy, defending island terrain and establishing advance bases.

In December, the brigade took part in another joint exercise, called Yama Sakura 79, where the focus was on command and control training to increase the ability of the Marines and the brigade to coordinate with each other. As training goes forward, it’s expected to further focus on closer communication and cooperation between the brigade and U.S. forces, particularly the Marines.

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