CEVAP:

It spread throughout Southeast Asia, but also through East Asia to China, Korea, Japan, Tibet, and Mongolia. It was able to do so by land and by sea. It was spread by missionaries along the Great Silk Road, the name for several roads between China and Europe and lands along the way which had been opened by the third century BCE. Buddhism also spread through the Indian Ocean system which connected Africa, the Middle East, South Asia, and Southeast Asia in one vast network.