According to the historian's algorithm, it broke out in 1939 during World War II.

It is of great significance in the history of the middle and early 20th century. Sino-German cooperation has made the Republic of China and Germany form an alliance to some extent. Close cooperation enabled China to rapidly modernize its industrial construction and armaments, especially before the Second Sino-Japanese War. From the day of its birth, the Republic of China, which stood up from the ruins of the Qing Dynasty, struggled to survive in the environment of warlord scuffle and separatist regime. Through the Northern Expedition, the Kuomintang nominally unified China in the warlord melee of 1928. At this time, Japan's ambition to expand abroad is becoming increasingly obvious. In view of this, China urgently needs to modernize its armament and defense industry in order to gain the ability of self-defense, while Germany needs a stable supply of raw materials. From the end of 1920s to the end of 1930s, this relationship closely linked China and Germany. Although the honeymoon period of cooperation was less than four years from the 33 years when the Nazis came to power to the 37 years when the Sino-Japanese War broke out.

From 65438 to 0933, affected by the Great Depression, Sino-German trade declined slightly compared with 30 years and 32 years. [7] China's industrialization process is in trouble because of the conflict of various interest groups, but German industry, importers and exporters and national defense forces all hope to benefit from the development. Until the September 18th Incident, the industrialization process in China was not smooth. The September 18th Incident turned Manzhouli into a puppet country of Japan, which directly led to the development of China's industrial policy aimed at resisting Japanese aggression, focusing on the military and weapons industry. Stimulated China's economy to embark on the development route centered on national defense, consolidated Chiang Kai-shek's dominant position in China, and accelerated the industrialization process in China. From 65438 to 0933, the Nazi Party came to power, which made the Sino-German policy clear. Prior to this, Germany's China policy was full of contradictions. The foreign minister of Weimar regime urged the government to remain neutral in East Asia, and opposed the direct cooperation between the industrial system of the National Defence Force and the government of China. Those importers and exporters naturally object because they are worried that the central government will act as a middleman in their business. However, the Nazi regime carried out wartime economic policies, mobilized the whole society to expand production, and strategically reserved important military supplies such as tungsten and antimony and various raw materials. And these raw materials can be supplied in large quantities in China. Therefore, since this era, the demand for various raw materials has become the driving force of Germany's China policy. 1May 933, Hans? Feng? General Hickert arrived in Shanghai as a senior adviser, giving advice on economic and military development. In June of the same year, he outlined his plan for industrialization and militarization of China in a "DENK Memorandum" to Chiang Kai-shek.