Amid sugar cane fields on a hill almost dead-center on far-flung Miyakojima island stands a facility that is at the forefront of Japan’s signal intelligence efforts.

There, on the outcrop 300 kilometers southwest of the main Okinawa island, are two silo-like buildings, each some 30 meters tall. Next to the silos is what, at first glance, appears to be a warehouse, also of similar height. The “warehouse” is shaped like a hexagon that has been split down the middle.

The three buildings have no windows. They are all painted green.

Interesting article at the Asahi Shimbun about the JSDF’s ramp-up of facilities, equipment, and exercises and how it’s all invariably pointed at China. The article itself is illuminating in pointing out some signals intelligence facilities not well known outside of the Japanese press.

I thought I’d provide some reference maps for the article, which ranges all over Japan. There are several installations mentioned in the article that start on the farthest periphery of Japan and end in the very heart of the country.

[cetsEmbedGmap src=,136.40625&spn=28.295639,41.308594&t=h&z=5&msid=208464819395951962634.0004998bc298ccc7b509e width=600 height=600 marginwidth=0 marginheight=0 frameborder=0 scrolling=no]

The island of Miyakojima, denoted on the map above. Miyakojima is part of the Ryukyu/Nansei islands, seized by the United States after World War II and returned to Japan in the 1970s. Miyakojima has been in the news lately because People’s Libration Army-Navy ships have been making for the open Pacific through the Miyako Strait. The Miyako Strait is between Miyakojima and Okinawa (see “Naha”) to the east. Scroll around a bit in the map and you’ll notice it’s a lot closer to Fuzhou than it is to Fukukoka.

Here’s a closeup of Miyakojima Sub Base in Google Maps. The SIGINT facility described in the article and in the accompanying photo is on the south side of the base.

[cetsEmbedGmap src=,125.326087&spn=0.007755,0.01296&t=h&z=17 width=600 height=600 marginwidth=0 marginheight=0 frameborder=0 scrolling=no]

Next up is Yozadake Sub Base on Okinawa, where according to the article, a stationary, 3-dimensional radar, the J/FPS-5, is currently under construction for monitoring the rest of the Nansei chain. This is my best guess:

[cetsEmbedGmap src=,+Japan&sll=26.094752,127.679973&sspn=0.024897,0.043344&ie=UTF8&ll=26.124791,127.706687&spn=0.006223,0.010836&t=h&z=17 width=600 height=600 marginwidth=0 marginheight=0 frameborder=0 scrolling=no]

It has a helicopter helipad. And it’s near Itoman, there are military vehicles present, and there appears to be construction going on. According to the article, the J/FPS-5 is known as the “Gamera” radar because of its resemblance to the monster Gamera.

Finally, here’s the vicinity of Fuchu Air Base, Tokyo, home base of the Air Self Defense Force’s Air Intellignce Wing. It’s somewhere in this neighborhood.

[cetsEmbedGmap src=,139.49049&spn=0.055502,0.103683&t=h&z=14 width=600 height=600 marginwidth=0 marginheight=0 frameborder=0 scrolling=no]

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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 530 post(s) on Japan Security Watch