1941 the rapid progress of the initial German air and land attacks into the Soviet Union made Red Army logistical support difficult because many depots (and most of the USSR's industrial manufacturing base) lay in the country's invaded western areas, obliging their re-establishment east of the Ural Mountains. Lend-Lease trucks and jeeps from the USA began appearing in large numbers in 1942. Until then the Red Army was often required to improvise or go without weapons, vehicles, and other equipment. The 1941 decision to physically move their manufacturing capacity east of the Ural mountains kept the main Soviet support system out of German reach. In the later stages of the war, the Red Army fielded some excellent weaponry, especially artillery and tanks. The Red Army's heavy KV-1 and medium T-34 tanks outclassed most Wehrmacht armor, but in 1941 most Soviet tank units used older and inferior models. Soviet-Japanese War (1945) While the Soviets considered the surrender of Germany to be the end of the “Great Patriotic War", at the earlier Yalta Conference the Soviet Union agreed to enter the Pacific Theater portion of World War II within three months of the end of the war in Europe. This promise was reaffirmed at the Potsdam Conference held in July 1945. The Red Army began the Soviet invasion of Manchuria on 9 August 1945 (three days after the first atomic bombing of Hiroshima and the same day the second atomic bomb was dropped on Nagasaki, while also being exact three months after the surrender of Germany). It was the largest campaign of the Soviet–Japanese War, which resumed hostilities between the Union of Soviet Socialist Republics and the Empire of Japan after almost six years of peace following the 1932-1939 Soviet-Japanese border conflicts. The Red Army, with support from Mongolian forces, overwhelmed the Japanese Kwantung Army and local Chinese forces supporting them. The Soviets advanced on the continent into the Japanese puppet state of Manchukuo, Mengjiang (the northeast section of present-day Inner Mongolia which was part of another puppet state) and via an amphibious operation the northern portion of Korea. Other Red Army operations included the Soviet invasion of South Sakhalin, which was the Japanese portion of Sakhalin Island (and Russia had lost to Japan in 1905 in the aftermath of the Russo-Japanese War), and the invasion of the Kuril Islands. Emperor Hirohito announced the surrender of Japan on 15 August. The commanding