Baci (Lao: ບາສີ; Thai: บายศรี, rtgs: bai si) and su kwan (Lao: ສູ່ຂວັນ; Thai: สู่ขวัญ, RTGS: su khwan; meaning "calling of the soul") is an important ceremony practised in Lao culture[1][2][3] and Northern and Isan Thai culture.
Baci is a phi ritual used to celebrate important events and occasions, like births and marriages and also entering the monkhood, departing, returning, beginning a new year, and welcoming or bidding etc.[1] The ritual of the baci involves tying strings around a person’s wrist to preserve good luck, and has become a national custom