For decades, Tetsuhiro Kinjo’s biggest worry was defending his mango trees against typhoons and marauding insects.

That was before the Japanese government decided to deploy missile launchers near his property on Ishigaki, a small subtropical island just 200 miles from Taiwan.

Over the past year, as China has carried out ever more overt displays of military force around Taiwan, Japan has grown increasingly concerned about the possibility of being drawn into a superpower conflict in its own backyard.