Introduction to stone drum: Stone drum is another form of door pillow stone, also known as boulder drum or stone ball. It is named because its shape is very similar to a drum. In religious sacrifices, drums are often used as instruments to ward off evil spirits and welcome gods. Because they are placed on both sides of the central door of Sanchuan Hall, they can not only stabilize the facade, but also function like stone shields, suppressing evil spirits and protecting them. The stone drum in Sanchuan Hall of Tianhou Temple in Lukang is a stone drum with thread carvings made of blue dou stone. There are no ornate carvings on the drum frame and base, but the overall feeling is simple, elegant and rustic.