An earthquake with a preliminary magnitude of 7.1 struck ​Japan’s southern Kumamoto prefecture on Tuesday, knocking out power to thousands ‌of homes, stopping rail services and triggering warnings for tsunamis and aftershocks. Companies including Sony and TSMC, the world’s largest contract chipmaker, have plants ​in the area of the quake. A Sony spokesperson ​said the company was checking the situation. TSMC did ⁠not immediately respond to a request for comment. The Japanese government ​issue...