Every late May or June; near the beginning of the Rainy Season; two little-known but archaic rituals are held in the environs of Chiang Mai; northern Thailand. These are the related Pu Sae and Ya Sae ceremonies; which are believed to pre-date the introduction of Buddhism to Northern Thailand. The traditions which they encompass similarly pre-date Thai and even Mon settlement in the area; and are associated with the Lawa; the earliest-known inhabitants of Chiang Mai.

According to tradition; Pu Sae and Ya Sae are the guardian spirits of Chiang Mai. Together with their son; Sudeva Rikshi; they wander the slopes of Doi Suthep (Suthep Mountain); where they are attended by six lesser spirits. Although they are now thought of as 'giants'; in their lifetimes Pu Sae and Ya Sae were almost certainly Lawa; the indigenous inhabitants of the region before the establishment of the Mon Kingdom of Haripunjaya (Lamphun); and whilst the Thai still lived mainly in South China.

Legend has it that Pu Sae; Ya Sae and their son were cannibals; who took great delight in human flesh. Once; when the Buddha was travelling in these regions; he passed through the area inhabited by the three cannibals. The fierce family followed his trail; intending to make a meal of him. Whilst meditating at Ban Panghai; Tambon Saluang; Mae Rim; the Buddha became aware of their intentions; and stamped on a boulder which to this day bears his footprint; and has become a shrine.