A Chinese takeover of Taiwan would make the threat to Japanese territory more acute, said Yuki Tatsumi, senior director at the U.S.-based Institute for Indo-Pacific Security. “Japan will no longer have a buffer, if you will,” she said, adding that it would face direct pressure from the Chinese navy.

China has fired rockets close to Taiwan in its most extensive military drills surrounding the self-governing island.

There has been a chorus of international criticism of China's drills.