China lodged a formal protest following the passage of a Japanese destroyer through the Taiwan Strait on April 18, coinciding with the anniversary of the 1895 Treaty of Shimonoseki, under which Taiwan was ceded to Japan from Qing dynasty China. The voyage by the JS Ikazuchi, en route to joint military exercises in the Philippines, sparked strong condemnation from Beijing, which described the transit as a deliberate provocation intended to undermine regional stability.

Chinese foreign ministry spokesperson Guo Jiakun criticized the 14-hour transit as evidence of Japan’s alleged intentions to militarily interfere in the Taiwan Strait, a flashpoint area sensitive due to Beijing’s claims of sovereignty over Taiwan. The timing of the passage on the historical treaty anniversary amplified tensions, with the People’s Liberation Army’s (PLA) official publication, the PLA Daily, stating the act not only hurt Chinese national sentiment but also heightened international vigilance against what it called Japan’s “new militarism.”

In response, China deployed its navy for training exercises in the western Pacific, including an unprecedented transit through the Yokoate Channel—closer to the Japanese mainland than the more commonly used Miyako Strait. The PLA’s Eastern Theatre Command described the maneuvers as routine and aimed at testing far-seas operational capabilities, denying any targeting of specific countries.

The JS Ikazuchi’s transit marked the fourth time a Japanese warship has passed through the Taiwan Strait since 2024 and was closely linked to Japan’s enhanced military engagement in the region. The destroyer was heading to participate in the annual Balikatan exercises—a large-scale joint military drill hosted by the Philippines and involving roughly 20 countries, including the United States, Australia, and France. This year, Japan has increased its commitment by deploying 1,400 personnel along with warships and aircraft, a significant escalation compared to previous years when Japan contributed only observers or limited assets.

The military activity is partly driven by Japan’s current Prime Minister Sanae Takaichi, who since assuming office last October has made statements endorsing the possibility of Japan’s Self-Defense Forces intervening in any conflict involving Taiwan—marking a notable shift in Japan’s post-war security posture. Takaichi also reiterated her intention to pursue an amendment to Japan’s pacifist constitution, which renounces war and prohibits the use of force in international disputes. Her Liberal Democratic Party holds a two-thirds majority in the lower house, an essential step toward constitutional revision, though a national referendum is still required.

Despite diplomatic friction, trade between China and Japan has expanded in the first quarter of 2026, with imports from China to Japan rising 29% to $44.7 billion and Japanese exports to China increasing by 7%. However, tourism flows have declined amid Chinese government travel advisories.

China’s protest extended beyond Japan, also targeting New Zealand for monitoring flights over the Yellow and East China Seas intended to enforce sanctions on North Korea. Wellington defended its reconnaissance operations as professional and compliant with international law.

The recent flare-up in the Taiwan Strait comes amid increasing US-led efforts to bolster regional security networks in the Indo-Pacific, pressing allies such as Japan to raise defense spending and participate more actively in joint operations. Japan’s expanded role in exercises like Balikatan and defense deals with partners such as Australia, including warship transfers and nuclear submarine collaboration, have drawn sharp criticism from Chinese media, which frames these developments as a resurgence of Japanese militarism tied to historical grievances.

As Japan moves forward with plans to revise its constitution and deepen military cooperation with regional partners, Beijing continues to monitor the situation closely, wary of further shifts that could alter the balance of power in East Asia.