China has a wide variety in geography with the Himalayas in the south, the Gobi desert to the north, many river valleys and mountainous regions in the center, and a large coastline with the Pacific Ocean. By 500 AD china had several very impressive dynasties, Xia, Shang, Zhou, Qin, and Han. After the Han dynasty, China was divided almost in half politically until the Tang empire reunited it.
The Mongol Empire rose to dominance in the 13th century in Asia, even though they were outside of China. The people of Japan were ruled by the Tokugawa Shogunate, which had an emperor at it’s highest position. They had separated themselves from the politics of China and Korea, resulting in a stable nation.
The earliest civilizations in India were based in the Indus Valley where the Indus River runs. Nearby was the Ganges River which eventually attracted civilization as well. While there is some variety, the geography of India is much simpler than Africa or China. Two religions have vied for importance in India throughout it’s history, those two religions are Buddhism and Hinduism.
As European nations continue to expand their colonizing influence around the world, China and Japan will remain mostly immune for a time. India however came entirely the control of the British Empire pretty quickly. Today, China, Japan, and India represent the three strongest Asian economies are quickly developing into world influences.