What the Large-Scale Purge of the Chinese Military and Passage Through the Taiwan Strait Mean — Tectonic Changes in the Northeast Asian Maritime Security Environment

In April 2026, the security environment in Northeast Asia is rapidly transforming under complex pressures. The ongoing large-scale purges within the People's Liberation Army (PLA), the release of footage by the Chinese military in response to the Japan Maritime Self-Defense Force (JMSDF) destroyer’s passage through the Taiwan Strait, and the blockade of the Strait of Hormuz are all interconnected manifestations of structural changes rather than isolated events.

First and foremost, attention should be drawn to the large-scale purges of PLA officials by President Xi Jinping. The ousting of the top uniformed officer, the Vice Chairman of the Central Military Commission, in January 2026 marks a culmination of a series of military purges, including the purges of Zhang Youxia and Fang Fenghui in 2017, the successive dismissals of Defense Minister Li Shangfu and former Defense Minister Wei Fenghe in 2023, and the mass removal of senior Rocket Force officials. The background to Xi's decision to eliminate what should have been his most trusted allies indicates that corruption and graft within the military are far more entrenched than anticipated, and that these issues may directly relate to operational capabilities, such as the actual deployment status of conventional warhead missiles and the procurement of equipment.

The impact of these purges on Japan's security is twofold. In the short term, the confusion in the command structure and the "standby state" of senior officials may reduce the PLA's capacity to plan large-scale military operations. In fact, subtle changes in the activity patterns of the Chinese military in the East China Sea and South China Sea have been observed from late 2025 to early 2026, with reports indicating a decreasing trend in the frequency of medium-range ballistic missile launch training. However, in the long term, the purges could lead to a military leadership solidified by loyalists taking bolder external actions. As Xi enters the latter half of his third term, with the timeline of the Taiwan issue in mind, the concern that risk-taking by loyal commanders may increase cannot be ignored.

In this context, the response of the Chinese military to the JMSDF destroyer's passage through the Taiwan Strait on April 17 is particularly significant. The Chinese military released footage of the passage on April 18 and issued a statement declaring, "We will resolutely prevent any attempts at external interference." The passage of JMSDF vessels through the Taiwan Strait is entirely legitimate under international law, having been conducted multiple times since the first passage in September 2025. However, the Chinese side's release of the footage and its use as a propaganda tool suggest a strategic escalation that goes beyond previous diplomatic warnings, indicating an awareness of mobilizing domestic public opinion and engaging in international cognitive warfare.

For Japan, this passage through the Taiwan Strait is not merely a declaration of freedom of navigation. As part of the "fundamental strengthening of defense capabilities" promoted by the Takai Cabinet since its inception in October 2025, efforts are underway to enhance the defense posture of the Nansei Islands and improve maritime denial capabilities. With a goal of raising defense spending to 2% of GDP by the end of fiscal year 2027, the budget for fiscal year 2026 allocates approximately 8.9 trillion yen, with early deployment of upgraded Type 12 surface-to-surface guided missiles (stand-off missiles) and expansion of the Southwest Mobile Surveillance Unit in progress. The increased presence in the Taiwan Strait symbolizes the external aspect of this defense posture enhancement.

At the same time, China's maritime activities are not limited to the Taiwan Strait. On April 18, it was confirmed that a Chinese survey vessel operated temporarily within Japan's Exclusive Economic Zone (EEZ) near the Senkaku Islands without Japan's consent. This incident indicates that China continues to conduct maritime survey activities in the East China Sea with military intent, reflecting a disregard for the "prior notification system" established by Japan.

As the de facto blockade of the Strait of Hormuz reaches seven weeks, Japan's security policy faces the dual challenge of addressing the energy crisis in the Middle East and military tensions in East Asia simultaneously. Japan relies on imports from the Middle East for approximately 95% of its crude oil consumption, and if the blockade of the Strait of Hormuz continues for an extended period, Japan may have to consider depleting its national reserves (approximately 220 days' worth). As the Takai Cabinet approaches its six-month mark, achieving domestic policies such as zero consumption tax is also a challenge, but enhancing deterrence in East Asia and responding to the situation in the Middle East are prioritized as urgent tasks.

Overall, the maritime security environment in Northeast Asia in the spring of 2026 is in an extremely unstable state, intertwined with the paradox of China's internal turmoil and external hardline posture, the progress of Japan's defense capability enhancement, and the ripple effects of the Middle East crisis. With the reliability of the deterrent power of the Japan-U.S. alliance being questioned like never before, the Takai Cabinet is required to make sophisticated strategic judgments that simultaneously promote the deepening of alliance relations and the enhancement of autonomous defense capabilities. Even if the purges within the Chinese military temporarily cause confusion in the command structure, there is no guarantee that this will reduce the risk of accidental conflict in the East China Sea or the Taiwan Strait; rather, it is necessary to recognize that it may increase unpredictability.