sentences:  Many of the more active ports came to have a port master, or head of the Japanese community; this port master, called "syahbandar" in Malay and Indonesia, oversaw the activities of the residents of the "Nihonmachi", served as a liaison between the community and the local authorities, and played an important role in coordinating the port's trade with non-resident Japanese traders who came to the port.For roughly three decades, Japanese communities across Southeast Asia thrived.This came to an end, however, in the 1630s, as the Tokugawa shogunate began to impose maritime restrictions; in 1635, Japanese were banned from travelling abroad, and from returning to Japan from overseas.