In 1944, with the resignation of Prime Minister Hideki Tojo, Yamada fell from political favor, and was reassigned in July back to Manchukuo as the final commander of the Kwantung Army, and he concurrently held the positions of Japanese ambassador to Manchukuo and Governor-General of the Kwantung Leased Territory. He quickly advised Imperial General Headquarters that it would be impossible to hold the border with the Soviet Union with the forces allocated, as the Kwantung Army had largely been hollowed out with redeployment of experienced troops (with most of their equipment) to the Pacific theater of the war. With no aid forthcoming from Japan, Yamada attempted to organize large numbers of poorly-trained conscripts and volunteers into eight new infantry divisions and seven new infantry brigades, and to withdraw from border areas to protect the strategic core of the nation. However, when the Soviet Army invaded Manchuria on 9 August 1945, many of Yamada's makeshift forces were no more than 15% combat ready and were quickly overrun.