Lying just 110 kilometers east of Taiwan, the rural Japanese island of Yonaguni is being militarized to strike at a theoretical Chinese invasion force. The U.S. is now planning to place missile-armed Marines on this island and its neighboring islands to bolster the Japanese defenses.
On a map, Japan’s Ryukyu island chain looks like a thin dragon’s tail that hangs from the southern part of Japan’s four main islands. The sprinkling of small and even smaller islands drop toward the southwest, eventually incorporating the larger island of Okinawa with its multiple Japanese and U.S. air bases and military installations.
South of Okinawa Island there is a long stretch of open ocean before the last stretch of the chain starts at Miyako Island. This 220 kilometer gap in the chain is called the Miyako Strait, and it is through this strait that China’s Liaoning aircraft carrier and its supporting warships passed in December 2022, on their way to practice attacking Japanese and U.S. targets from positions in the Philippine Sea.
From Miyako Island, the island chain swings west, and from the Yaeyama islands one has to sail due west to find the small island of Yonaguni, which is the most westerly point of Japan. Yonaguni lies 1,050 kilometers from Japan’s main islands, but only 110 kilometers from Taiwan, making it a very strategic island as Japan prepares to deter a possible Chinese invasion of Taiwan.
On a map, the island of Yonaguni looks roughly like a leaf that’s 11 kilometers long and 4 kilometers wide. A small fishing village harbors most of the island’s 1,700 people, while the rest of the island is covered by a modern airport with a 2,000-meter-long runway, grassland farms, and hills covered in jungle foliage that offers good cover for dug-in units.
An interesting fact about Yonaguni is that it is home to a massive offshore, submerged stone formation called the Yonaguni Monument. This huge stone formation looks freakishly much like an ancient man-made construction that sank under the ocean tens of thousands of years ago, making it one of the most interesting and controversial scuba dive sites in the world.
The strategic value of the sleepy island of Yonaguni is that it is a large, unsinkable weapons and sensor platform positioned close enough to Taiwan to threaten an invasion force with long-range precision missiles and anti-ship missiles. The flip side of being an unsinkable platform is that it can’t move, so it can be targeted more easily than the sinkable variety. The obvious solution to being targeted by China’s long-range missiles would be to dig in deep and dig secretly, while also deploying multiple defensive missiles alongside the offensive ones.
In 2014, Japan announced that it would station 160 troops and build a radar station on Yonaguni. In 2021, the government announced that it would deploy hundreds of soldiers as well as anti-ship and anti-air missiles to Ishigaki, a larger island just 105 kilometers east of Yonaguni.
In August last year, Yonaguni’s residents were shocked when six Chinese missiles impacted near their island after China launched aggressive military exercises in the wake of then-U.S. House Speaker Nancy Pelosi’s visit to Taiwan. On January 10 of this year, Japan announced that it has begun to strengthen the island’s military base and has deployed an air-defense missile unit on the island.
The U.S. has now also indicated that it wants to deploy Marines armed with missiles to the islands of Okinawa prefecture, which includes Yonaguni and the larger Yaeyama islands just east of Yonaguni. The plan is to deploy a new rapid reaction force called a Marine Littoral Regiment to the most strategic islands in the Ryukyu chain if conflict seems imminent. This force will eschew most of the artillery and armor that the Marine Corps formerly used in favor of lightweight weapons and missile systems.
Instead of standing back and seeing how a possible Chinese attack will pan out, the idea is to “stand in” by having heavily armed Marines in position next to their Japanese counterparts on Japan’s most vulnerable islands — before Chinese forces can take these strategically valuable platforms. This new concept of “littoral” pre-positioning of Marines on Japanese islands was forced on the U.S. by new developments in China’s ability to sink aircraft carriers and shoot down warplanes far away from China’s coastline. China now has hundreds of long-range ballistic missiles and hypersonic missiles that it says can track and destroy moving U.S. carriers far away from China’s coastline.
As it is possible that Beijing is not bluffing about its new weapons that are designed as “area denial” tools to keep U.S. carriers and warplanes far away from Taiwan, the Pentagon now plans to turn Japan’s frontline islands into “unsinkable aircraft carriers.” Or rather, given the fact that the runways on the Ryukyu islands can be cratered by Chinese missiles, these islands would be more like unsinkable missile bases rather than aircraft carriers.
By being located so close to Taiwan’s eastern coastline, Yonaguni Island and its close neighbors are excellent platforms from which to observe and use long-range missiles to attack Chinese warships, warplanes and missiles as they circle Taiwan during an invasion. Japan and the U.S. are increasingly preparing to deter such a theoretical invasion, meaning that China might have a big incentive to invade Japan’s westernmost islands, if it decides to invade Taiwan.
Such an invasion of Yonaguni Island would require massive missile barrages and bombing runs by ground-attack jets, followed by waves of amphibious landing forces. China might also use special forces that would swim ashore from submerged submarines to sow chaos and terror in the hours before an attempted amphibious landing. These would be the kind of scenarios that the U.S. Marines and their Japanese counterparts would be training to expect, survive and repel.