The waterwheel, also known as the Kongming cart, is the oldest agricultural irrigation tool in China, a superb labor skill created by our ancestors in the process of conquering the world, and a precious historical and cultural heritage. According to legend, Bilan is the prototype of Emperor Ling of Han Dynasty, which was popularized and used in Shu after being improved by Kong Ming of the Three Kingdoms. It was widely used in agricultural irrigation in Sui and Tang Dynasties, with a history of 1700 years.

In ancient times, waterwheels had many meanings. As shown in the figure below: