How did chinas geography limit its contact with other regions?

 Ancient China was built along the two main rivers—first the Yellow River (Huang He) in the north, and later the Yangtze in the south.  In the settlements along the Yellow River, people grew millet in the rich, easily worked loess soil. In the south, people grew rice along the Yangtze river, ate a good deal of fish, together with vegetables, especially water plants such as water chestnuts and lotus.  Along with dogs, pigs and cattle, people in the south had water buffalos to help work the soil.  By the heavy use of human labor, the same area of land in the south could grow about twice as much food as in the north.


All Under Heaven     The seasonal monsoon winds that blow north from the Indian Ocean over Asia produce vast amounts of rainfall in the Himalayan Mountains and the Tibetan Plateau.  Some of this water, along with rich sediments, flows across the Chinese Plain creating fertile farmland. The fertile areas of Eastern China are surrounded by deserts, vast steppes, high mountains and impassable jungles.  Because of this the early civilization of China developed more independently than those of the Indus, Tigris and Euphrates, and Nile River valleys, which were always in contact with each other.  This gave rise to a feeling in China was the world, that it was "All Under Heaven", surrounded by lesser regions populated by barbarians.

Hope this helped! 

Pilgrims is the answer