At certain Buddhist ceremonies where you wish to conferr good luck such as house warmings and house blessings, sai sin is used. Sai sin is the unspun white thread which is rolled up in oval shaped ball used by monks. The sai sin ball is placed in front of the alter tables and is used to mark the ceremonial perimeter by taking the ball out through a window and then circling the building. The ball is returned to the altar and the head monk will hold the ball during the ceremony. During the chanting, he will unroll the sai sin and passes the thread through his fingers before passing the ball to the next monk. Each monk will hold a piece of the thread and pass the ball until it reaches the last monk. The connection between the monks and the thread is thought to form a sacrosanct circle as the monks chanting infuses the thread with sacred power. It is believed that anyone who is within the circle will be blessed and protected from harm and evil.
Sai sin is also used during the preordination ceremony. Ceremonial attendants use it to tie the ordination candidate’s wrists to ward off evil spirits. Before the candidate is ordained he is believed to be vulnerable to danger and needs extra protection during the rites.
Sai sin is used in the North and Northeast for different purposes. The thread is tied onto the visitors’ wrists and they are wished a safe journey and good health. It serves as a gesture to welcome the visitors’ to the host’s home. In the North and Northeast regions, sai sin is also used in a traditional wedding ceremony. Guests at the wedding reception woud tie pieces of white thread around the wrists of the bride and groom to wish them happiness and prosperity. This is in contrast to the common Thai tradition of pouring lustral water on the bride and groom’s hands.