It’s really happening: Japan is getting Marines. Corey Wallace at Sigma1 summarizes from a Asahi article that hasn’t made it into English yet.

According to an Asahi Shimbun article here (jp), the MoD plan to convert a GSDF infantry regiment into a US-style amphibious unit is proceeding. Given the rapid modernization of Chinese defense forces, the plan will become an important part of the new and revised defense guidelines to be released at the end of the year. The new unit’s prime responsibility will be filling the perceived Nansei Island security vacuum between Tsushima and Yonaguni islands, which is 1200 kilometres North-South and 900 kilometres East-West. With an estimated 2500 islands, the only permanent forces responsible for the islands’ protection are the Okinawan 15th Brigade and a garrison on Tsushima (JGSDF Tsushima Area Security Force), with the rest being covered by the GSDF Western Army Infantry Regiment(Light) (WAiR) stationed in Nagasaki prefecture. WAiR’s ability to cover the region in case of an armed landing is, and has been in doubt for some time.

The thinking here is that either the JGSDF 8th Division (in Kumamoto) or an infantry regiment from the 15th Brigade be converted to not only provide relief in the case of disaster and other emergencies but also be equipped to recover islands taken by hostile forces. The model will be the US Marine Corps concept, and since 2006 WAiR and the 8th Division have already been training with the US Marines in California in activities related to recovering lost islands. (Link)

Here’s the area of operations for the new unit, as seen in Google Earth.

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Japan is smart in creating a unit to retake islands, instead of concentrating on garrisoning them with troops. Trying to defend all 2,500 islands would be a fool’s errand. Once an island is isolated by air and naval power the success of any reasonably well executed amphibious invasion is guaranteed. But once landed, the tables are turned and the invasion force can then become equally isolated and then defeated. Japan should make an effort to garrison the larger populated islands, but the GSDF can’t be everywhere.

The training with the US Marines the article is referring to is Iron Fist, an exercise held every two years at Camp Pendleton, California. Here’s an article about the 2006 exercise, and an article about the 2010 exercise. Note that in 2006, the U.S. Marines state that the Japanese don’t know anything about amphibious warfare, and are learning how to handle small inflatable boats to land companies. In 2010, they seem to have progressed to putting vehicles ashore by landing craft.

Regarding the “Western Infantry Regiment”…this unit is rather mysterious. It does not appear on the Ministry of Defense’s organizational chart for the GSDF. Web searches reveal nobody has a lot to say about it. The name sounds rather bland and makes it sound like just another infantry unit. Not so. It is, in fact, as far as I can tell a 700-man unit–in U.S. terms more like a battalion–of diver and small boat-trained infantry. (Tora at has some pics here.)

My guess is that a regular infantry division will get the nod. Every country needs a light infantry shock force, and that’s the Western Infantry Regiment. At 700 troops, it’s too small to accomplish the mission of retaking anything but the smallest of islands. Expanding it would just dilute the quality of the unit.

On the other hand, a Japanese infantry division has a personnel complement of 7,000-8,000, who can be retasked and retrained, and let go if necessary. Training for amphibious warfare is going to cost a lot of money, and the defense budget is still falling. Cutting manpower would increase the quality of the remaining forces while freeing up funds for training. In fact, as I mentioned a few weeks ago, cutting the GSDF by two divisions to create a brigade of Marines (from 14,000 to 3,500) to save money might be even better.

Should it be the 8th Infantry Division? Maybe not. The 8th Division in Kyushu provides a depth to Japan’s southern defenses and a local reserve. Pull it away and southern Kyushu, the part of the Home Islands closest to potential fighting, loses half of its garrison.

If anything, one of the divisions in Hokkaido, way to the north, should be redeployed south and retrained as Marines. With the end of the Soviet invasion threat to northern Japan there are two divisions and two brigades in Hokkaido doing essentially nothing.

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Geographically, the 7th Division in Chitose would be ideal. It’s far north, away from the prying eyes of the PLA. It’s based in a port town, and a cursory check of Chitose’s port facilities in Google Maps seem to indicate they would be a fine embarkation point for amphibious troops. And there are several local islands that could be studied or used to practice amphibious operations. In case of a a conflict, the eastern side of Japan should be relatively safe, allowing an amphibious task force to steam south sheltered behind the Home Islands and the collective might of the SDF.

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A contributor and editor at the blog War Is Boring, Kyle Mizokami started Japan Security Watch in 2010 to further understand Japan's defenses and security policy.
Kyle Mizokami has 596 post(s) on Japan Security Watch