At the time, China was fraught with factional warlordism and foreign incursions. The Northern Expedition (1928) nominally unified China under Kuomintang (KMT) control, but Imperial Japan loomed as the greatest foreign threat. The Chinese urgency for modernising its military and national defence industry, coupled with Germany's need for a stable supply of raw materials, put China and the German Weimar Republic on the road of close relations from the late 1920s onwards. That continued for a time following the rise in Germany of the Nazis. However, intense co-operation lasted only until the start of the Second Sino-Japanese War in 1937. The German co-operation nevertheless had a profound effect on the modernisation of China and its ability to resist the Japanese during the war.