charge of Germany's concessions at Qingdao, and spent heavily to set up modern facilities that would be a showcase for Asia. Japan seized the German operations in 1914 after sharp battles. After World War I, the German republic provided extensive advisory services to the Republic of China, especially training for the Chinese army. Colonel General Hans von Seeckt, the former commander the German army, organized the training of China's elite army units and the fight against communists in 1933–1935. All military academies had German officers, as did most army units. In addition, German engineers provided expertise and bankers provided loans for China's railroad system. Trade with Germany flourished in the 1920s, with Germany as China's largest supplier of government credit. The last major advisor left in 1938, after Nazi Germany allied itself with Japan, the great enemy of the Republic of China. Nevertheless Chiang Kai-shek continued in his hopes to use Germany as a model for his nation, as his mentor Sun Yat-sen had recommended. Although intense cooperation lasted only from the Nazi takeover of Germany in 1933 to the start of the war with Imperial Japan in 1937, and concrete measures at industrial reform started in earnest only in 1936, it had a profound effect on Chinese modernization and capability to resist the Japanese in the war. Finance minister of China and Kuomintang official H.H. Kung and two other Chinese Kuomintang officials visited Germany in 1937 and were received by Adolf Hitler. At the same time, the exiled German Communist Otto Braun was in China as a Comintern agent, sent in 1934, to advise the Chinese Communist Party (CCP) on military strategy and taking a major part in The Long March under a Chinese name, Li De (); it was only many years later that Otto Braun and "Li De" came to be known as the same person. World War II (1941–1945) Sino-German cooperation collapsed in 1939 due to the start of World War II in Europe, forcing many Chinese nationals to leave Germany due to increased government surveillance and coercion. The example Japan set in the Second Sino-Japanese War forced Hitler to replace China with Japan as the Nazi's strategic ally in East Asia. Following the Japanese Attack on Pearl Harbor in 1941, the Chinese declared war on Germany, which resulted in the Gestapo launching mass arrests of Chinese nationals across Germany. At the end of the war,