In February 1941 Aung San, working with Japanese intelligence, left Hla Myaing in Bangkok. He then secretly re-entered Burma and began efforts to contact and recruit additional Burmese agents to work with the Japanese. Aung San's preparations for the mission included being fitted with a pair of false teeth by a Japanese dentist and receiving a Japanese passport from the Japanese Ministry of Communications. He entered the colony secretly through the port of Bassein, changed into a longyi, and booked a train to Rangoon using a pseudonym. By 8 July 1940 he had recruited thirty of his old revolutionary colleagues and smuggled them out of the country via Japanese intelligence networks. These "Thirty Comrades" were taken to the Japanese-occupied island of Hainan for further training. Aung San was twenty-five, the third-oldest of the group. The Thirty Comrades trained for six months on Hainan with Suzuki Keiji and other Japanese officers. Aung San, Ne Win, and Setkya all received special training, since the Japanese intended to place them in senior positions in the Burmese government following the Japanese conquest of the territory.