Japan’s recent warning that a Chinese attack on Taiwan would pose a “survival-threatening” risk to Tokyo marks a sharp departure from decades of strategic ambiguity and risks undermining international law, regional stability, and Japan’s own constitutional commitments, a legal expert has warned.
Dr Nicksoni Filbert, a lecturer at the University of Dar es Salaam’s Faculty of Law, said the statement made by Prime Minister Sanae Takaichi in November represents an unprecedented escalation in Japan’s posture toward Taiwan and China, with immediate diplomatic and economic consequences.
“This is not a statement that advances regional security,” Filbert said in an interview. “It stretches the boundaries of self-defence under international law and injects tension into a region that was becoming increasingly interdependent and cooperative.”
For decades, Japan has maintained a carefully calibrated ambiguity on Taiwan, aligning with the 1972 China–Japan Joint Communiqué in which Tokyo said it “understands and respects” Beijing’s position that Taiwan is part of the People’s Republic of China.
“If Taiwan is treated as China’s internal matter under the One China Principle, then any Japanese military intervention would amount to interference in the domestic affairs of another state,” he said, citing Article 2 of the United Nations Charter.
Under Article 51 of the UN Charter, self-defence is permitted only when a state is attacked by another state. Taiwan, Filbert noted, is not Japanese territory, nor is it recognised by Japan as a sovereign state capable of invoking collective self-defence.
“There is no legal nexus that allows Japan to claim self-defence over military action in Taiwan,” he said.
Dr. Filbert also pointed to Japan’s post-war constitution, particularly Article 9, which renounces war and the use of force to settle international disputes.
Although Japan reinterpreted its security policy in 2015 to allow limited collective self-defence, Dr. Filbert said the threshold remains high: an attack on a close ally that threatens Japan’s survival and endangers Japanese lives.
“Taiwan does not meet those criteria under Japan’s own legal framework,” he added.
China’s response to the statement was swift. Beijing imposed restrictions on rare earth exports, suspended cultural exchanges, conducted military exercises, and curtailed tourism flows, moves that Filbert described as creating “unnecessary economic shock” for both sides.
“Japan and China are deeply interconnected economically,” he said. “Statements of this nature have real-world consequences for businesses, supply chains, and tourism.”
Dr. Filbert said Japan’s colonial history in Asia amplifies the impact of such rhetoric. Japan ruled Taiwan for nearly five decades and occupied large parts of China during the first half of the 20th century. This period resulted in an estimated 15 to 20 million Chinese deaths.
“To China and other Asian states, this kind of language evokes memories of Japanese militarism,” he said. “Those concerns are not abstract; they are rooted in lived history.”
Dr. Filbert outlined several difficult paths now facing Japan’s leadership: fully retracting the statement, clarifying it while preserving ambiguity, prioritizing economic cooperation over military signaling, reassessing its dependence on the United States, or pursuing constitutional revision to expand military powers.
None of the options, he said, is without cost.
The United States, Japan’s key security ally, has itself maintained strategic ambiguity on Taiwan. Recent signals from Washington urging both Beijing and Tokyo to lower tensions have contributed to a softening of rhetoric, Dr. Filbert said.
“The irony is that even the U.S. has been ambivalent,” he noted. “That makes Japan’s clarity on military intervention all the more striking.”
Dr. Filbert warned that a military confrontation between China and Japan, both among the world’s four largest economies, would carry severe global consequences.
“Conflict between major economic powers would not be contained,” he said. “The ripple effects would be global, with a real risk of escalation into a wider war.”
Despite the sharp rhetoric, Filbert said he sees signs of de-escalation, with fewer public exchanges and a lowering of diplomatic tone.
“I would advise measured concern, not panic,” he said. “Military preparations will continue, but overt confrontation is not inevitable.”
Ultimately, Filbert argued, diplomacy remains the only viable path forward.
“Peace is not idealism, it is necessity,” he said. “Only through restraint and dialogue can regional and global stability be preserved.”