Rapid Transformation of the Security Environment in Northeast Asia: China's and North Korea's Approach and the Japan Self-Defense Forces' New Developments

In mid-April 2026, the security environment in Northeast Asia is rapidly transforming due to several significant developments. The visit of Chinese Foreign Minister Wang Yi to Pyongyang, North Korea's testing of cluster warheads for ballistic missiles, and the groundbreaking participation of Japan's Self-Defense Forces in live-fire exercises during the U.S.-Philippines joint exercise "Balikatan" have been reported in quick succession. While these three movements may appear independent, they should be viewed as part of a chain reaction that has the potential to fundamentally rewrite the balance of power in Northeast Asia.

First and foremost is the visit of Chinese Foreign Minister Wang Yi to North Korea from April 9 to 10. This marks the first visit by a Chinese foreign minister to Pyongyang in approximately six and a half years since September 2019, and its symbolic significance is extremely high. Wang Yi met with North Korean Foreign Minister Choe Son-hui, and they agreed to strengthen exchanges and cooperation between the two countries throughout 2026, which marks the 65th anniversary of the signing of the Sino-Korean Friendship Cooperation Mutual Assistance Treaty in 1961. This treaty stipulates mutual defense obligations, and the expression of "strengthening strategic communication" suggests a deepening of military cooperation that goes beyond mere diplomatic rhetoric.

Notably, Kim Jong-un's statements are significant. According to reports from North Korean state media on April 11, Kim Jong-un expressed "full support" for China's "One China" principle, marking the first time he has publicly acknowledged China's One China principle. North Korea's stance on the Taiwan issue has traditionally been pro-China, but explicit mention at the top level represents a new dimension. Simultaneously, the content read by the Chinese side included an assessment that North Korea has "successfully overcome isolation and pressure from the United States and Western forces," which can be interpreted as a clear challenge from both China and North Korea to the international community's sanctions regime against North Korea.

The backdrop of Wang Yi's visit to North Korea includes rumors of a possible meeting between President Trump and Kim Jong-un in Beijing in May. At the 9th Congress of the Workers' Party of Korea on February 26, Kim Jong-un expressed a willingness for dialogue, but he stipulated that the United States must recognize North Korea's status as a "irreversible nuclear power." China is seen as aiming to play the role of mediator in U.S.-North Korea dialogue, aligning with its strategic intent to prevent the expansion of U.S. security influence on the Korean Peninsula. South Korea's Ministry of Unification is urging both China and the United States to resume dialogue with North Korea, but North Korea has consistently rejected inter-Korean dialogue, revealing an intention to weaken the U.S.-South Korea alliance by excluding South Korea from future dialogue processes.

Secondly, the advancement of North Korea's missile technology is raising serious concerns. During ballistic missile launch tests conducted on April 7 and 8, the KN-25 short-range ballistic missile and the KN-23 (also known as Hwasong-11A) were launched. The launch of the KN-25 disappeared in the early flight phase, indicating a high likelihood of failure. However, the two KN-23 missiles flew approximately 240 kilometers and 700 kilometers, respectively, and North Korean state media claimed that the KN-23 was equipped with cluster warheads. This warhead is said to be capable of dispersing small munitions over an area of 16 to 17 acres (approximately 6.5 to 7 hectares).

The deployment of cluster warheads can be positioned as a countermeasure against South Korea's interception systems. While conventional warheads concentrate impact points in a single location, cluster warheads disperse munitions over a wide area, making complete interception by systems such as the Patriot missile or THAAD extremely difficult. There are also suggestions that Iran may have learned from its experience using cluster munitions in conflicts with Israel and the United States, indicating that North Korea's weapon development is reflecting real combat data from other countries.

Thirdly, the significance of Japan's Self-Defense Forces participating in this year's "Balikatan" exercise is extremely high. This joint exercise, hosted by the Philippines and the United States, will take place from April 20 to May 8, with participation from Australia, Japan, Canada, France, and New Zealand. This marks the first time Japan's Self-Defense Forces will participate in live-fire exercises, reportedly contributing to the sinking of decommissioned vessels using the Type 88 Surface-to-Ship Guided Missile.

The significance of this participation has dual layers. First, conducting practical anti-ship missile training far south of the southwestern islands is understood in the context of the southwest defense strategy aimed at preventing the Chinese Navy from breaking through the first island chain, embodying the concept of deep defense in the Philippine Sea. The Type 88 Surface-to-Ship Guided Missile is expected to be updated to an enhanced version of the Type 12 Surface-to-Ship Guided Missile in the future, which is noteworthy in relation to the development status of extended-range variants. Second, Japan's substantial expansion of multilateral security cooperation frameworks not only strengthens the mutuality of the U.S.-Japan alliance but also embodies the recent trend of deepening security cooperation with Australia and the Philippines through concrete military exercises.

When these three movements are analyzed integratively, a picture emerges of simultaneous progress in "the cohesion of the authoritarian camp" and "the strengthening of the democratic camp's response" in Northeast Asia. The rapprochement between China and North Korea is being reinforced in the context of mutual defense based on military treaties, while North Korea's nuclear and missile capabilities continue to improve both quantitatively and qualitatively. On the other hand, the responses of allies, including Japan, are shifting from a traditional "shield" to include "spear" capabilities, with the participation of the Self-Defense Forces in live-fire exercises abroad symbolizing a significant step in this direction.

South Korea's position is particularly complex. Kim Jong-un's theory of "two hostile states" fundamentally overturns the previous premise of Korean unification, and the response from the South Korean Minister of Unification with a "peaceful two-state theory" suggests a transformation of the very foundation of inter-Korean relations. Amid increasing uncertainty regarding the U.S.-South Korea alliance, North Korea's intention to exclude South Korea from the dialogue process represents one of the most dangerous scenarios for Seoul.

The focus going forward will be whether a meeting between President Trump and Kim Jong-un can be realized during Trump's planned visit to Beijing in May, and to what extent the United States can compromise on references to denuclearization in that case. At the same time, the progress of Japan's defense capability development plans and the actual operational capabilities of the Self-Defense Forces demonstrated during the Balikatan exercise must also be closely monitored as factors that will directly impact the regional balance of power.