Nearly ten Chinese and Russian military aircraft entered South Korea's air defense identification zone (KADIZ) on June 27, prompting Seoul to scramble fighter jets and lodge formal diplomatic protests with Chinese and Russian defense attachés [4][5]. JoongAng Ilbo reported the number as more than ten [9]. The incursion occurred on the same day that Japanese Defense Minister Shinjiro Koizumi arrived in Seoul for a two-day visit aimed at expanding bilateral defense cooperation [3].
South Korea's Joint Chiefs of Staff stated that the aircraft — assessed to be part of joint Chinese-Russian air drills — entered and then departed the KADIZ without violating South Korean territorial airspace [4][10]. The JCS characterized the flights as brief and likely connected to joint training [9][11]. Radio France Internationale reported that the aircraft included bombers and fighters, and noted that a similar incursion had taken place in December 2025 [11]. Le Monde likewise recalled the December incident, in which both Japan and South Korea had criticized the flights and deployed fighters in response [12].
Despite the JCS assessment that no airspace violation occurred, the South Korean government treated the KADIZ entry as a provocation requiring both a military and a diplomatic response. Seoul summoned the Chinese and Russian defense attachés to deliver formal protests [5]. South Korean Air Force fighters carried out tactical measures in response to the incursion [10]. The BBC reported that such entries into the KADIZ by Chinese and Russian aircraft have recurred since 2019 [5].
China's Ministry of National Defense described the flights as the 11th joint strategic air patrol conducted with Russia, carried out under an annual bilateral military cooperation plan [14]. The ministry framed the patrol as a routine feature of Sino-Russian defense relations. Vedomosti, a Russian business daily, reported the patrol covered the western Pacific, the Sea of Japan, and the East China Sea, and noted the previous patrol in December 2025 [14]. Gazeta.ru, a Russian outlet, reported the KADIZ entry and the South Korean fighter scramble, noting that no airspace was violated [13].
The incursion coincided with the conclusion of defense talks between Koizumi and South Korean Defense Minister Ahn Gyu-back. The two ministers agreed to continue advancing exchanges between their countries' aerobatic teams — the Black Eagles and Blue Impulse — to further develop maritime search and rescue exercises, and to pursue cooperation in advanced science and technology fields including artificial intelligence [2]. The joint press statement also referenced cooperation in space and unmanned aerial vehicles [16][18].
The aerobatic team exchanges carry particular symbolic weight. Japan had previously refused to provide refueling support for South Korea's Black Eagles over a territorial dispute concerning the Dokdo islets, an issue the two ministers resolved in a December phone call. That resolution led to the first refueling of a South Korean military aircraft by Japanese forces in late January [3]. Koizumi's visit to Seoul — the first by a Japanese defense minister in roughly a decade — included paying respects at the Seoul National Cemetery and a planned visit to an Air Force base alongside Ahn [3][8]. Nikkei reported that the refueling support was regarded as a symbolic step in bilateral defense cooperation [7].
The South China Morning Post reported that the two countries agreed to upgrade their defense pact to counter threats from China and North Korea, and reaffirmed trilateral coordination with the United States [16]. A CSIS analysis framed the bilateral defense ties as part of a broader "free and open Indo-Pacific" strategy, noting that both Japan and South Korea are extending security engagement to Southeast Asian states, with implications beyond the immediate Northeast Asian theater [17]. DefenceTurk reported that the ministers agreed to hold annual trilateral exercises with the United States against North Korean threats [18].
Beijing offered a different reading of the Japan-South Korea defense relationship. China's Ministry of Foreign Affairs stated that countries' exchanges and cooperation should not harm regional understanding and trust, should not target third parties, and should not undermine regional peace and stability [15]. Guancha, a Chinese state-affiliated outlet, cited analysts warning that a potential Japan-South Korea Acquisition and Cross-Servicing Agreement (ACSA) risks evolving into a military alliance targeting China, and reported the ministry's position that "亚太地区不需要军事集团，也不需要新冷战的'小圈子'" (the Asia-Pacific does not need military blocs or new Cold War "small circles") [15].
No independent security analysts, civil society organizations, or legislative voices from Japan, South Korea, or any other country were quoted in the available reporting. The Russian government's strategic rationale for the joint patrol was not articulated by any named Russian official in the sources reviewed.
The next scheduled step in the Japan-South Korea defense relationship is the continued development of the aerobatic team exchanges and search and rescue exercises outlined in the joint press statement [2]. Whether the KADIZ incursion alters the pace or scope of those plans has not been addressed by either government.