Not many people seem to know that Germany had a close relationship with China until 1941, and until 1937 was its principal arms supplier (which is one reason why it’s hard to support the claim, which I saw someone recently make on Twitter. that WWII began in 1937 with the
Marco-Polo bridge incident). During the six-week Shanghai-Nanking campaign of 1937 the Japanese lost 70,000 troops, one tenth of their total force in China. When I asked the Japanese military historian Ikuhiko Hata about this staggering figure (given in the Cambridge History of
Japan, vol 6), he told me that although most Chinese troops were poorly trained peasants, the elite units trained and armed by the Germans had superior equipment to the Japanese and inflicted very heavy heavy casualties on them. The phone below shows a Chinese troops wearing
German helmets during the Shanghai-Nanking campaign. 
Among the Nazi leaders Georing in particular was a strong believer in an alliance with China, which he thought in the long run would become a greater power than Japan.However
Hitler needed the Japanese as potential allies against the Soviet Union, so when the Japan-China war began in 1937, he banned any new military oorders from a China, although he allowed already ordered weapons (and spare parts) to be delivered. The German-Japanese relations went
into a temporary crisis when Germany signed the Molotov-Ribbentrop pact without informing the Japanese and Chiang Kai-shek had hopes for resuming the German alliance, but they were ended when Japan signed the tripartite alliance in 1941. Then following the Japanese attack on
Pearl Harbor, Hitler declared war on the US and China on Germany. Defying German hopes, Japan never declared war on the USSR.
