A celebration of beginnings, commemorating not just the Buddha’s first sermon but also his conception and the day he renounced his royal life to become an ascetic.
Asalha Puja also known as Dhamma day is observed on Guru Purnima, commemorates the Buddha's first teaching after enlightenment at Sarnath to his five disciples.
"Asalha Puja"
It celebrates the birth of the Buddhist sangha and of Buddhism as a religion.It also marks the beginning of monsoon season, during which monks traditionally do a "vassa" or rains retreat, where they abstain from traveling & engage themselves in spiritual upliftment.
"Buddhist sangha"
The Buddha delivered the Dhammacakkappavattana Sutta, or the Wheel of Dharma which comprises of the 4 noble truths & the 8 fold path.
"Dhammacakka"
Vassa concludes with the pavarana ceremony & the lively kathina ceremony, in which groups of laymen present gifts to the monks, takes place during the first month following the conclusion of vassa.Only countries belonging to the Theravada tradition celebrate Dhamma Day such as Indonesia, Cambodia, Thailand, Laos, Myanmar.
"Vassa"
The significance of Dhamma day is that it celebrates both the teaching and also the human capacity to understand the teachings of Buddhism.