For decades, residents of Japan's southern island of Okinawa have strongly opposed the US military bases in the region, seeing them as sources of crime and pollution. But a subtle shift is underway, driven by Chinese sabre-rattling and economic challenges. "If we think about the security of Japan and of east Asia, the presence of bases on Okinawa is inevitable in a way," says Ryo Matayoshi, a municipal councillor in the Okinawan city of Ginowan.