Vesak

Vesak commemorates the birth, awakening and death of the Buddha, and it does so on a single day in the Theravada world because the tradition holds all three fell on the same full moon.

The month is Vesakha in Pali, corresponding roughly to April or May. The date is therefore lunar, and it moves in the Gregorian calendar. Where it moves to depends on which lunisolar calendar a country uses, and the Buddhist countries do not use one calendar.

Sri Lanka, Cambodia and Malaysia generally take the first full moon of May. Thailand, Laos and Singapore reckon by their own lunar month, which can put the observance a month apart from a neighbour's in years when the intercalary month falls differently. Myanmar keeps its own. The differences are calendrical, not doctrinal.

The World Fellowship of Buddhists, at its founding conference in Sri Lanka in 1950, resolved to promote the observance of the full moon day of May as Vesak, and the United Nations recognised the day in 1999. Neither imposed a single date, and the resolutions were framed to accommodate the existing variation.

East Asian Buddhism separates the three events entirely. China, Korea, Japan and Vietnam keep the Buddha's birth on the eighth day of the fourth lunar month, in Japan, fixed to 8 April in the Gregorian calendar after the Meiji calendar reform, and observe the awakening as Bodhi Day and the death as Nirvana Day on separate dates.

So the question of when Vesak falls has no single answer, and the reasons are entirely mechanical.

If the festival's date is variable, the date it commemorates is far more so.

Two chronologies have long competed. The long chronology, from the Sri Lankan Pali sources, places the death in 544 or 486 BCE depending on how the regnal figures are handled, giving a life of about 563 to 483 BCE. That is the date in older reference works and in the Buddhist Era used officially in Thailand, Sri Lanka, Myanmar and Cambodia, which counts from 544 BCE and is why those countries number the year in the twenty-five hundreds.

The short chronology, from Indian and Chinese sources, places the death around 368 BCE.

Since a symposium organised by Heinz Bechert in the 1980s the scholarly centre of gravity has moved to a date of death somewhere between roughly 410 and 370 BCE, about a century later than the traditional figure and closer to the short chronology. The anchor for all of these is the reign of Ashoka, independently datable because his inscriptions name Hellenistic kings whose dates are known.

Excavation at Lumbini published in 2013 reported a timber structure beneath the later brick shrine with radiocarbon dates in the sixth century BCE, which the excavators presented as supporting the earlier chronology. The interpretation of the structure has been questioned.

The practical result is that the official Buddhist Era year, printed on documents in several countries, rests on a chronology most specialists no longer accept. This causes nobody any difficulty, which is itself worth noticing.