After WW2, Germany was split into a democratic/capitalist west, and communist east, until the break-up of the Soviet Union. The capitalist portion of Germany was on good terms with the US, while the communist half was part of the Soviet sphere.

Japan is a similar story. The old monarchy was replaced with a democracy, and American money flowed into Japan. During the latter half of the 20th century, the Japanese economy boomed, with a focus on technology and automation/machinery.

China and the Soviet Union weren't "enemies" of the US except in the context of opposing economic ideologies, being capitalism and communism. They never fought each other except by proxy war (Afghanistan, Angola, Cuba, Vietnam among other wars).