The Thay Pagoda is located at the foot of Sai Son Mountain in Quoc Oai, Ha Tay. The Thay Pagoda Festival is the opportunity to worship sorcerer Tu Dao Hanh; a Buddhist monk who became king and created the Vietnamese water puppet show.

The festival is held every year from the 5th to the 7th of the 3rd lunar month. The main celebration is on the 7th. The festival begins with Buddha's worship and platform running; a religious performance supported by traditional music in a solemn atmosphere.

During the festival, numerous games are played. The most famous performance is the water puppet show, given in front of the Thuy Dinh, or Temple on water.

After ceremonies for Buddha, visitors enjoy hiking while admiring all the beauties of the Doai region. Visitors also enjoy hearing the many famous legends that enrich the traditional value of that beautiful region.