One Ordination Split into Separate Lineages Across Asia

The Buddha's original ordination of monks in the sixth or fifth century BCE produced a single monastic community, but as Buddhism spread across Asia in the following centuries different regions preserved different versions of the ordination lineage and its rule: the Theravada countries of Sri Lanka and Southeast Asia kept the Pali Vinaya of the Theravada school, while China, Korea and Vietnam adopted the separate Dharmaguptaka Vinaya lineage, so that a monk ordained in Thailand and a monk ordained in Korea today stand in entirely different, independently transmitted ordination lines even though both trace their authority back to the same historical founder.

The women's full ordination lineage, which requires ordination by both an order of bhikkhus and an order of bhikkhunis together, died out in the Theravada countries many centuries ago, apparently for lack of a surviving bhikkhuni order to complete the required joint ordination, while a bhikkhuni lineage did survive within the separate East Asian ordination tradition. Since the 1990s and 2000s a revival movement has used that surviving East Asian bhikkhuni lineage to re-establish full ordination for women within Theravada Buddhism, a move some senior Theravada monastic authorities in Thailand and elsewhere reject as lineage-invalid, while other Theravada teachers and entire monastic communities, particularly in Sri Lanka, have accepted and continued it, leaving the validity of the modern Theravada bhikkhuni ordination a live and unresolved dispute within the tradition itself.