When a unit of the Ground Self-Defense Force was deployed to Japan's westernmost island of Yonaguni for the first time six years ago, it felt like a boon to the remote community, which had long been suffering from a falling population and a weak economy.

The arrival of the troops, many together with their families, has invigorated the sleepy island in many ways: They brought more children to schools, while bars and restaurants boomed and local festivals leaped back to life with more participants.

Nevertheless, according to some, that integration into local life has come at a cost. They say it has made it hard to voice concerns over the troops' presence — concerns that have only grown since Russia's invasion of Ukraine and the fear that Moscow's actions could embolden China to press its own territorial claims more aggressively in nearby waters.