Japan’s Ministry of Defense has confirmed that a Chinese Dongdiao-class electronic intelligence (ELINT) ship transited eastward through the Miyako Strait into the Pacific Ocean on November 4, prompting a full-spectrum monitoring operation by the Japan Maritime Self-Defense Force (JMSDF).
Defense Minister Shinjiro Koizumi, who assumed office in October 2025, stated that the ministry maintains a continuous nationwide surveillance posture in response to increasing Chinese naval intelligence activity near Japan’s maritime approaches.
In a formal briefing, Koizumi detailed that the Dongdiao-class vessel moved from the East China Sea toward open waters of the western Pacific, passing through the internationally recognized Miyako Strait between Okinawa and Miyako Islands. The ship was closely tracked by the JMSDF destroyer Genga, with additional surveillance provided by maritime patrol aircraft and radar systems based in multiple regions.
“This vessel is equipped to carry out wide-area electronic information gathering using radar and other sensors,” Koizumi explained. “The Self-Defense Forces maintained continuous situational awareness throughout its transit.”
The Dongdiao-class, known in Chinese as the Type 815, is a sophisticated electronic reconnaissance platform used by the People’s Liberation Army Navy (PLAN) to monitor foreign radar emissions, communications, and electronic signatures. These vessels play a central role in China’s maritime intelligence network, collecting data that can be used for operational planning, electronic warfare, and precision targeting.
According to Japan’s Defense Ministry, the ship’s movement on November 4 was part of a recurring pattern of Chinese naval intelligence operations near Japan. Ministry maps released with the statement show earlier transits by similar vessels in September near the Tsushima Strait and in October through the Tsugaru Strait, both key maritime passages between the Japanese home islands.
“This sequence of activities represents a sustained reconnaissance effort encircling Japan’s surrounding waters, particularly areas close to major sea lanes,” Koizumi said.
The ministry emphasized that Japan’s monitoring operations are conducted on a 24-hour basis, coordinated across multiple JMSDF regional commands. Units from Sasebo, Kure, Yokosuka, and Misawa participated in tracking and information-sharing efforts. Maritime patrol aircraft, likely P-1 and P-3C Orions, were dispatched to maintain visual and electronic contact as the vessel progressed eastward.
While the Dongdiao-class is not a combat vessel, its intelligence-gathering capabilities are considered strategically important. The ships are designed to collect and analyze radar signatures, radio frequencies, and communication patterns from allied naval and air forces operating in the region. Analysts note that this information feeds into China’s broader goal of mapping the electromagnetic environment across the western Pacific—a critical step in modern warfare planning.
Japan has routinely monitored similar transits through international waterways, viewing them as legal but strategically sensitive. The Miyako Strait, a deep-water corridor south of Okinawa, is particularly significant as it provides the PLAN with a direct route from the East China Sea into the Philippine Sea and beyond the so-called first island chain—a geographic barrier that shapes Chinese military strategy in the Indo-Pacific.
Koizumi reaffirmed Japan’s intent to maintain a measured and sustained response to such operations. He expressed gratitude to Self-Defense Force personnel involved in the mission, praising their professionalism and readiness.
“The Self-Defense Forces will continue to respond appropriately and steadily,” Koizumi said. “I appreciate the commitment of our personnel who protect Japan’s sea and airspace every day.”
The ministry underscored that Japan’s surveillance not only ensures national security but also contributes to shared allied situational awareness across the Indo-Pacific region. Through cooperation with U.S. and partner forces, Japan helps monitor Chinese military activities extending into the Pacific, reinforcing collective deterrence.
Defense experts say the increased frequency of Chinese ELINT vessel movements reflects Beijing’s expanding intelligence focus on Japan and allied naval operations. The activity coincides with ongoing U.S.-Japan joint exercises in the Philippine Sea and heightened regional tensions surrounding Taiwan and the South China Sea.
While Tokyo has refrained from direct diplomatic protest over the transit—acknowledging the ship’s passage through international waters—officials view the incident as another reminder of China’s persistent effort to map the operational environment around Japan.
As Koizumi concluded in his statement, “Our forces remain vigilant. Safeguarding Japan’s territorial integrity and ensuring stability in surrounding seas will continue to be our foremost priority.”
