The "China Security Report 2027" released today by the "National Defense Research Institute", a think tank of the Ministry of Defense of Japan, pointed out that China is focusing on the possibility of using force against Taiwan in the future and actively strengthening its military control capabilities in the South China Sea. It intends to block the Bashi Strait between Taiwan and the Philippines when a conflict breaks out in the Taiwan Strait, prevent the US military from intervening, and launch attacks on southern Taiwan from the direction of the South China Sea. The report emphasizes that for China, which is pursuing the reunification of Taiwan and launching strategic competition with the United States, the South China Sea has become an extremely important sea area related to strategic success or failure.
This year's analysis of China's security strategy, with the theme of "China and the South China Sea - An Aspects of Maritime Issues", analyzes the strategic transformation of the Chinese navy, militarization of the South China Sea and coast guard activities, as well as the impact of US-China strategic competition on regional security. However, the National Defense Research Institute also emphasized that this report is an independent analysis conducted by researchers based on public information and does not represent Japan's official position.
The second chapter of the report was written by Masashi Iida, who studies China's military issues, and analyzes China's military purpose of controlling the South China Sea from the perspective of "Taiwan reunification and U.S.-China strategic competition."
The report pointed out that China has indicated that it will not rule out the use of force to reunify Taiwan, and has repeatedly held military exercises to encircle Taiwan since 2022. The Chinese military attaches particular importance to southern Taiwan and the Bashi Strait, because once a war breaks out in the Taiwan Strait, whether it can control this strategic channel connecting the South China Sea and the Western Pacific will directly affect China's ability to fight against Taiwan and the US military's ability to intervene.
The report quoted Meng Xiangqing, a professor at the National Defense University of China, as an analysis of the military exercise around Taiwan in August 2022. He pointed out that at that time, China set up an exercise area in southern Taiwan. One of the purposes was to be able to block and control the Bashi Strait and send a strong signal to external interference forces. Based on this analysis, the National Defense Research Institute concluded that China is planning to block the Bashi Strait to prevent the US military from entering the South China Sea in the event of a conflict in the Taiwan Strait.
The report further analyzed that if China can block the Bashi Strait and gain advantages in the sea and airspace south of Taiwan, the People's Liberation Army can proactively launch offensive operations against southern Taiwan from the South China Sea, including launching attacks on military bases and cities in southern Taiwan. At the same time, if China can maintain its military superiority in the central and southern parts of the South China Sea, it will also help prevent the US military from approaching the theater from Oceania and the Indian Ocean.
In other words, China's fight for control of the South China Sea is not only to assert maritime rights and interests, but also to create favorable conditions for possible future military operations against Taiwan and to weaken the US military's ability to intervene in wars in the Taiwan Strait.
The report also pointed out that China's naval strategy has gradually shifted from "offshore defense" in the past to taking into account "offshore defense and open sea defense". In recent years, it has strengthened its combat capabilities away from homeland. In addition to protecting maritime lines of communication and overseas interests, its purpose also includes containing the U.S. military in waters beyond the first island chain and expanding the strategic depth of China's military operations.
The report takes the two aircraft carrier formations of the Chinese Navy "Liaoning" and "Shandong" entering the Pacific Ocean at the same time from May to June 2025 as an example. It points out that there is a view that the two aircraft carrier formations may conduct exercises to simulate a military confrontation between the United States and China. Among them, the Liaoning fleet crossed the second island chain and sailed to the waters near Minamitori Island in Japan, while the Shandong fleet entered the Pacific through the Bashi Strait and headed for the vicinity of Okinotori Island.
The report analyzed that if the above speculation is true, the Liaoning ship may play the role of a US aircraft carrier formation, while the Shandong ship will conduct confrontation exercises. This shows that the Chinese military is exploring an operational model that uses the South China Sea as a base to project military power to the Western Pacific via the Bashi Strait.
In addition, the South China Sea is also an important stronghold for China's nuclear deterrence against the United States. The report pointed out that China has deployed six strategic nuclear submarines on Hainan Island. If the activities of the US military in the South China Sea can be excluded, it will help ensure the safe operation of nuclear submarines carrying submarine-launched ballistic missiles and maintain its nuclear counterattack capability against the United States.
In addition to military deployment, China also continues to expand its control area in the South China Sea through the "trinity" operation of the navy, coast guard and maritime militia. The report points out that China uses "gray zone" means that have not yet reached the level of formal military conflict to gradually accumulate fait accompli and promote the so-called "salami-slicing strategy." The ultimate goal is to exclude the US military and other foreign military forces and turn the South China Sea into a sea area fully controlled by China.
The report believes that the South China Sea issue has evolved from a territorial dispute between China and Southeast Asian countries to a major stage of military confrontation between the United States and China, and is inseparable from Taiwan's security. For Japan, in addition to continuing to strengthen security cooperation with the United States and other allies, it is also necessary to strengthen cooperation with ASEAN countries, including providing radars, patrol ships and maritime surveillance-related equipment to maintain freedom of navigation and regional security.
The report finally pointed out that the South China Sea not only involves China’s territorial claims and maritime rights and interests, but also is connected with major interests related to the legitimacy of the Chinese Communist Party’s governance, such as the reunification of Taiwan and the strategic competition between the United States and China. Therefore, it is expected that Beijing will continue to pursue control of the South China Sea in the future, and tensions in East Asian waters may be difficult to ease.
