With regard to the smuggling trade between China and Japan（including the smuggling trade with Wang Zhi and others） in the 16th century，which was also known as the Warring State Period in Japan，there are only few original historical data left in Japan. After researching deeply into the Yatsushiro Diariesof Sagara Family （compiled by the Historiographical Institute of the University of Tokyo），combined with relevant notes in History of Ming Dynasty，Tanaka Takeo （1923-2009），expounded that the ships going for Ming Dynasty from Shiranuhi Sea operated by Sagara Family in Kyushu Higo were not officially recognized by the Ming Dynasty government，while meaning that they were not official foreign trade ships managed by maritime trade commissioner. Sagara Family，as one of members，together with Oouchi，Ootomo，Matsura，Shimadzu，Sou and other noble families jointly constitute a powerful support for Wako Pirates.