Yongxiang. It required Du's diplomacy and finances to save his mentor, who after the release stood down almost immediately, turning his criminal empire over to Du. Now known as the "zongshi" (宗師) or "grandmaster" of the criminal underworld, Du controlled gambling dens, prostitution, and protection rackets, as well as setting up a number of legitimate companies — including Shanghai's largest shipping corporation and two banks. With the tacit support of the police and colonial government, he also now ran the French Concession's opium trade, and became heavily addicted to his own drug. Alliance with the Kuomintang As the leader of the Green Gang, Du dominated Shanghai's opium and heroin trade in the 1930s, and secretly funded the political career of Chiang Kai-shek. In contrast to his views on legality, Du was politically a staunch Confucian conservative. He had close ties with Chiang Kai-shek, who in turn had ties to both the Green Gang and other organised secret societies from his early years in Shanghai. Chiang forged political alliances throughout the 1920s, with some of the secret societies going as far as to offer their support in the 1927 Shanghai Purge. The resulting massacre ended the First United Front, and as a reward for Du's service, Chiang appointed him as the president of the Shanghai Board of Opium Suppression Bureau. The end result was that Du came to officially control the entirety of China's opium trade. The Green Gang's support for the Nationalist Government included funding and equipment, even going as far as to purchase a German Junkers 87 emblazoned with the Board of Opium Suppression Bureau logo. In return, Du was given leeway to run labour unions and keep business flowing freely. In 1931, Du had the financial and political clout to open his own temple — one dedicated to his ancestors and family members — and hold a three-day-long party to honour its grand opening. It was one of Shanghai's largest celebrations, with hundreds of celebrities and political figures attending. Within months of its opening, however, the temple's private wings had been turned over to the manufacture of heroin, making it one of Shanghai's largest drug factory. When the Second World War broke out in 1937, Du offered to fight the Japanese by scuttling his fleet of ships at the mouth of the Yangtze River, but he eventually fled. Green Gang operatives cooperating with Dai Li, Chiang's intelligence chief,