Why would the Soviet Union have ordered an invasion of Japanese-held Manchuria two days after the atomic bombing of Hiroshima?

During 1931 Japan had invaded Manchuria without declarations of war, breaching the rules of the League of Nations. Japan had a highly developed industry, but the land was scarce of natural resources. Japan turned to Manchuria for oil, rubber and lumber in order to make up for the lack of resources in Japan.

Explanation:

"germany's geographic location was an advantage when it was on the offensive in the war because it was situated next to an extremely wide river, the rhine, which was difficult for the allies to cross."