What step did China take during the Ming dynasty to isolate itself from the rest of the world?

They isolate China from foreign influence and focus on internal development. By the end of the fifteenth century, imperial subjects were forbidden from either building oceangoing ships or leaving the country. This was done to stop exportation and importation of goods between China and outside world. The main focus is for China to develop what they have and no to relate with outside world.

Explanation:

The Ming dynasty ruled china from 1368 to 1844. The Ming dynasty ruled between Yuan and Wing dynasties. They tried to isolate China to reduce foreign influence and focus on their own internal development. They belief that china was perfect and have all the needed resources for development. Exploration was not encouraged and consequently naval technology stopped improving. They didn't need outside trade, they were a large country that don't need outside resources and technology.

the united states began searching for a way to reduce oil

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