In February 1938, on the advice of his newly appointed foreign minister, the strongly pro-Japanese Joachim von Ribbentrop, Hitler ended the Sino-German alliance with the Republic of China to instead enter into an alliance with the more modern and powerful Empire of Japan.
At first, Churchill welcomed Chamberlain's appointment but, in February 1938, matters came to a head after Foreign Secretary Anthony Eden resigned over Chamberlain's appeasement of Mussolini, a policy which Chamberlain was extending towards Hitler.
With Japanese casualties and costs mounting, the Imperial General Headquarters attempted to break Chinese resistance by ordering the air branches of their navy and army to launch the war's first massive air raids on civilian targets. Japanese raiders hit the Kuomintang's newly established provisional capital of Chongqing and most other major cities in unoccupied China, leaving millions dead, injured, and homeless.