Chinese Coast Guard Begins Patrols East of Taiwan, Adding New Pressure on Japan and the Philippines

The Taiwan Coast Guard Administration revealed on July 4 that it was tracking Chinese Coast Guard vessels in the eastern waters of Taiwan. Reuters reported the same day that China had begun coast guard patrols east of Taiwan despite international backlash. Al Arabiya also reported that Chinese vessels were being monitored off the eastern coast of Taiwan. The issue is that this is not merely a coastal policing activity, but rather an attempt to push into the waters on the eastern side of Taiwan, which connects maritime routes between Japan and the Philippines.

The Significance of the Waters East of Taiwan

The Taiwan Strait to the west of Taiwan has already become a space where activities by Chinese military aircraft and vessels are normalized. In contrast, the waters east of Taiwan provide a space for the Taiwanese Navy to retreat and conserve its strength, as well as an operational area for the U.S. military and the Self-Defense Forces when approaching from the Philippine Sea. The distance from Yonaguni Island to Taiwan is about 110 kilometers, and the Bashi Channel is a critical point connecting the southern tip of Taiwan and northern Luzon Island. The presence of coast guard vessels in these waters under the guise of "law enforcement" should be seen as an attempt to change the perception of the maritime area at a lower threshold than deploying warships.

Coast Guard Vessels Are Not a Minor Issue

Coast guard vessels are not destroyers. However, this does not lead to the conclusion that they can be taken lightly. The Chinese Coast Guard combines large ships, long-duration operations, radio warnings, and inspection requests to restrict the actions of opponents just short of military conflict. The Financial Times reported on July 3 that China is intensifying its claims over the waters east of Taiwan. This is not just the movement of a single vessel, but a process of establishing the maritime area itself as a "space that China can manage."

Pressure on Japan and the Philippines

Nikkei Asia pointed out on July 2 that China's push east of Taiwan is testing the deterrence of Japan and the Philippines. This perspective is valid. For Japan, the waters east of Taiwan are related to the defense of the Nansei Islands, while for the Philippines, they represent a maritime surveillance line north of Luzon. Even if both countries monitor separately, China can exploit the gaps. The focus will be on how quickly information from the Japan Maritime Self-Defense Force's P-1 patrol aircraft, SH-60K and SH-60L patrol helicopters, the Air Self-Defense Force's E-2D, the Japan Coast Guard's patrol vessels, and the Philippine Coast Guard's surveillance can be shared.

• The waters east of Taiwan serve as a rear maneuvering space in the event of a Taiwan contingency.
• The Bashi Channel is a chokepoint in the SLOC connecting Japan, Taiwan, and the Philippines.
• Coast guard activities are more ambiguous than military actions and can delay political judgments.

Blind Spots in Alliance Operations

The Japan-U.S. alliance appears strong when discussing aircraft carriers, missiles, and submarines. However, in situations where coast guard vessels are sailing at low speeds, asserting "jurisdiction" over the radio, and applying pressure on Taiwan and third-party vessels, it is difficult to respond solely with military force. If the Self-Defense Forces take action, China will criticize the militarization, and if only the Japan Coast Guard responds, the burden of continuous monitoring will increase. This intermediate domain is a practical challenge for the defense of the Nansei Islands.

In my view, the focus this time is not on the number of Chinese coast guard vessels. The issue is that the Chinese side has begun to accumulate actions that it can call "normal operations" in the waters east of Taiwan.

What Is Needed Is Not Flashy Countermeasures

This is not a simple matter of Japan immediately increasing its naval deployments. Rather, what is needed is to shorten the time lag between publicly available and classified information among Japan, the U.S., Taiwan, and the Philippines. If the positions, courses, radio communications, and nearby commercial shipping tracks of coast guard vessels cannot be shared in a matter of hours, the small pressures on the ground will turn into diplomatic post-approval.

During the Cold War, the Japan Maritime Self-Defense Force learned to defend SLOCs by tracking Soviet submarines. The current adversary uses not only submarines but also white-hulled coast guard vessels. The true challenge is not to possess strong weapons, but to determine who will respond, at what point, and with what authority to ambiguous actions. If this is delayed, the waters east of Taiwan will become narrower without a fight.