Dhamma Day also known as Asalha Puja, is a Theravada Buddhist festival. Observed mainly in Cambodia,Thailand, Sri Lanka, Lao PDR and Myanmar, the celebration falls on the first full moon of the eight lunar month in the Thai calendar. On this special day, Buddhists express gratitude for the teachings of the Buddha.
Asalha Puja celebrates Buddha’s first sermon which took place about 2,500 years ago in Deer Park in Benares, India. The sermon, also referred to as ‘setting the wheel of Dhamma into motion’, encompassed the teachings of Buddha, called the four noble truths, which include suffering (dukkha) the knowledge of suffering caused by craving (tanha); a state beyond dukkha and tanha, nirvana and the way to nirvana, which is via the Noble Eightfold Path.
This first sermon was not the only first structured discourse given by Buddha after his enlightenment but it also contained the essence of all Buddha’s subsequent teachings. At the end of this sermon, one of the five participants requested to be Buddha’s disciple, which Buddha granted. This established the first order of Buddhist monks or the founding of Buddhist sangha.
On Asalha Puja , Buddhist monks recite the Eight Precepts, give sermons and lead meditations, conduct chanting and lead a candle light procession around the temple three times. Devotees give offerings to the monks.
The Rainy Season Retreat or Vassa, which is a three-month period of meditation by monks begins the day after Asalha Puja.