Together with Christianity and Islam, Buddhism, known as the world's three major religions, was founded by Sakyamuni in the northern part of the ancient South Asian subcontinent in the sixth and seventh centuries BC. It has been established and grown in the influence of doctrines, organizations, etc., and in constant struggle with them. In the course of its development, Buddhism was still more or less influenced by other sects, and because believers had different understandings of doctrines and precepts, many sects emerged in history.From the point of view of the ancient South Asian subcontinent, roughly speaking, the more primitive Buddhist sects aimed at self-interest to achieve the liberation of Arhats, and they were called Theravada Buddhism; Mahayana Buddhism emerged around the 1st century AD, and they used altruistic bodhisattvas to become Buddhas. for the ultimate purpose.The Hinayana only recognizes Sakyamuni as a Buddha, while the Mahayana believes that there are as many Buddhas as Ganges sands in the world.After the 7th century AD, some sects of Mahayana Buddhism merged with some Brahmanism systems with a secret religious nature at that time, forming Tantric Buddhism (Tantra).Hinayana, Mahayana, and Esoteric Buddhism, these are the three major schools of Buddhism that gradually formed during the popularization of ancient South Asian subcontinent.They have their own transmission and flow, and they will not be abandoned in parallel.

Buddhism gradually spread to countries and regions adjacent to the South Asian subcontinent, and various sects were formed, each with its own national characteristics.The original three major sects were introduced into China at different times. Generally speaking, they spread gradually in the Central Plains of China where the Han nationality is the main body, and were mainly introduced into ancient Korea, Japan and other places through China, which is called Northern Buddhism. Also known as Sinicized Buddhism.Its teachings are mainly based on Mahayana, and some of Theravada and Esoteric Buddhism are mixed.Its classics belong to the Chinese system.It was gradually formed in the Tibet region of China, known as Tibetan Buddhism, and later spread in Mongolia and other regions.Its teachings are a mixture of Buddhism (including a large number of esoteric elements) and the local primitive religion "Bonjiao", and Buddhism, especially esotericism, is the main one.Its classics are mainly in Tibetan.It was introduced into today's Sri Lanka, Myanmar, Thailand, Cambodia, Laos and Southeast Asia, and spread in the ethnic minority areas in Southwest China, which is called Theravada Buddhism.The teachings are mainly based on Theravada, and its classics mainly belong to the Pali system.China is a country with three major factions, and in terms of the number of believers and the vastness of the spread area, it is a country dominated by Sinicized Buddhism.