In 2003, he was invited to become a visiting foreign researcher by Kansai University and conducted research in Japan for two months (June and July 2003) on the history of the Japanese community in prewar Hong Kong.

In July 2003, he accepted an invitation to join a multinational research team (mainly comprising Japanese and US scholars) to conduct a three-year research project (2004-2006) on Confucian ethics and Japan's Modernization sponsored by the Shibusawa Foundation, Japan.