In the past, some casting experts
believed that there were two pouring heads at the top of the Yongle
Bell. In 1989, research personnel of our museum found a pouring
head at each of the four joints between the handle and the body of
the bell. The rain - type casting technique made it possible for
the molten bronze to flow into the pouring heads evenly. So the
shape of the bell was not damaged, blowholes and air holes were
prevented effectively, and looseness of the internal structure of
the bell was avoided. The Yongle Bell has been struck for more than
500 years, but it has never produced any unpleasant sound. This
proves the compact structure of the cast.