China Coast Guard's Permanent Presence East of Taiwan and the Upcoming JL-3 Test: Japan's SLOC Defense

Behind the patrol vessel of the Taiwan Coast Guard docked at Keelung Port, a white hull of the China Coast Guard has been lingering about 54 nautical miles east of Taiwan. Since July, what has caught the author's attention is that this white hull and the submarine-launched ballistic missile that flew from the South China Sea to the Pacific on July 6 appear to be separate events but are actually placed on the same maritime map.

According to Defense News, the China Coast Guard has continued its patrols on the Pacific side east of Taiwan since May, and on July 4, it rotated its fleet. The Chinese side describes this as a "normalized law enforcement cruise." The Taiwanese side has protested, claiming it violates international law and undermines regional stability. Furthermore, the report states that on July 6, China launched a ballistic missile from a submarine, which reportedly flew approximately 7,000 to 7,300 kilometers and fell in the South Pacific with a simulated warhead.

The Low Pressure Created by the White Hull

From the perspective of the Japan Maritime Self-Defense Force, the emergence of military vessels is straightforward. It is easy to assemble a sequence of actions involving escort ships, patrol aircraft, intelligence gathering, and diplomatic protests. However, the Coast Guard vessels are different. Even if armed, their nominal purpose is law enforcement. While claiming to be "restraining," they gradually exhaust the counterpart's security agencies, port authorities, air surveillance, and political judgments.

The troublesome aspect of the current actions east of Taiwan for Japan is that the location is not within the Taiwan Strait but rather on the Pacific side, closer to the outer side of the First Island Chain. The waters extending from the eastern coast of Taiwan to Yonaguni, Ishigaki, Miyako, and further to the Bashi Channel overlap with Japan's SLOC (Sea Lines of Communication) and the U.S. military's reinforcement routes. If the white hull is stationed here, China can observe the eastern exit in a "non-military conflict" form before any emergency arises, creating psychological constraints on the shipping routes.

It Is Not a Question of JL-2 or JL-3

Regarding the submarine-launched ballistic missile on July 6, there are suggestions that it could be either JL-2 or JL-3. However, there is no need to definitively determine the model at this point. The larger significance is that the Chinese Navy conducted a long-range strategic missile launch from the South China Sea towards the Pacific, albeit with prior notification.

Reports indicate that the missile was equipped with a training warhead and fell into the South Pacific near Nauru and Tuvalu. New Zealand and Australia expressed concerns that this contradicts the spirit of the South Pacific Nuclear-Free Zone Treaty. Japan should not treat this type of launch merely as a distant nuclear arms control issue. The launch area, transit route, and drop area all relate to Japan's southern shipping routes and the rear bases of its allies.

Reading Capability and Intent Separately

China's capabilities are layered. The first is the long-term deployment capability using the Coast Guard. Large Coast Guard vessels have extended range and a lower political threshold than military ships. The second is the strategic demonstration capability of submarine-launched ballistic missiles. This serves to show the U.S., Australia, New Zealand, and Japan that China's nuclear deterrence is not limited to land-based missiles.

So what is the intent? In the author's view, Beijing is not assuming just one crisis scenario. Instead of repeatedly conducting military exercises directly in front of Taiwan, it is expanding peacetime maritime management with the permanent presence of the Coast Guard in the east while simultaneously applying psychological pressure on distant allies with submarine-launched missiles. In other words, it is designed to slow down the decision-making speed of neighboring countries before a crisis begins.

Japan's Weakness Is Not Just the Number of Escort Ships

In response, calls for increasing the number of P-1 patrol aircraft, escort ships, and Japan Coast Guard patrol vessels will naturally arise. However, simply increasing the number of vessels will lead to a delayed response if the white hull and ballistic missiles cannot be depicted on the same operational map. Information exchange among the Japan Coast Guard, Ministry of Defense, Ministry of Foreign Affairs, U.S. military, and Taiwan is well-established as peacetime procedures, but how long can it endure if a gray situation continues for weeks?

Especially along the line from Yonaguni to Miyako, Okinawa Main Island, and northern Philippines, it is necessary to overlay the position information of Coast Guard vessels, signs of submarine activity, changes in civilian shipping routes, and the burden of air surveillance onto a single common map. During the Cold War's anti-submarine warfare, threats were primarily underwater. Now, the white hulls above the surface and the strategic weapons below the surface are aiming for the same political effect.

Deterrence Can Erode from a Distance

The two actions this time are not incidents where gunfire erupted in Japan's nearby waters. That is why they can easily be underestimated. However, the anxiety surrounding the South Pacific's nuclear-free zone, the permanent presence of the Coast Guard east of Taiwan, and reactions to maritime discussions between Japan and the Philippines are all movements testing the will of allies outside the First Island Chain.

The real challenge is not to guess the names of the new missiles of the Chinese Navy. It is to treat the permanent presence of the white hull as a law enforcement issue and the submarine-launched ballistic missiles as a nuclear arms control issue, while overlooking the common operational intent that exists between the two.

Japan's SLOC defense is no longer just a problem for Japan's nearby waters. Small frictions occurring around the east of Taiwan, north of the Philippines, and in the island nations of the South Pacific can erode deterrence before reaching Yokosuka or Sasebo. The speed at which this realization occurs is what is currently being tested in the Japan-U.S. alliance.

Main References

• Defense News, July 15, 2026, “First the coast guard, then an ICBM: China tests new, long-term ways to hold off rivals in Asia”
• Defense News, July 7, 2026, “Chinese ballistic missile test is said to undermine nuclear weapons-free zone in South Pacific”