Later generations revered Lu Ban as an exemplary ancient craftsman, attributing numerous tools and inventions to him. Each attribution needs to be assessed against specific written sources.
Worship within craft communities and the memory of trades helped spread these stories. The historical individual, accounts of the Gongshu family, and popular tales of Lu Ban belong to different layers of tradition.
The craftsman in tradition
Lu Ban (c. 507–444 BC) was an ancient Chinese master carpenter, architect, structural engineer and inventor during the Spring and Autumn period of the Eastern Zhou Dynasty. He is revered as the Chinese Deity (Patron) of builders and contractors.
Lu Ban was born in the state of Lu; a few sources claim he was born further to the west, in Dunhuang, to a family of carpenters or artisans during the Spring and Autumn period of the Zhou dynasty. His original name was Gongshu Yizhi. He was also referred to as Gongshu Ban or Pan. He was supposed to have been an indifferent pupil until his love of learning was kindled by the scholar Zi Xia. He later learned woodworking from Bao Laodong. The great demand for his work supposedly compelled him to invent or improve several carpenter's tools—the saw, the square, the planer, the drill, the shovel, and an ink marking tool—to complete his many projects more quickly. His wife was also credited with inventing the umbrella in order to permit him to work in inclement weather.
Lu Ban is revered as the god of carpentry and masonry in Chinese folk religion. His personality is assumed by the master carpenter involved in the construction of houses among the Kam people. He is sometimes counted among the Five Kings of the Water Immortals, Taoist water gods invoked by sailors for protection while carrying out journeys.
He is referenced in a number of Chinese idioms. The Chinese equivalent of "teaching one's grandmother to suck eggs" is to "brandish one's axe at Lu Ban's door". His cultural companion is the stone worker Wang Er, who lived around the same time.
A story about invention and war
Mozi travelled from one crisis zone to another throughout the ravaged landscape of the Warring States, trying to dissuade rulers from their plans of conquest. According to the chapter "Gongshu" in the Mozi, he once walked for ten days to the state of Chu in order to forestall an attack on the State of Song. At the Chu court, Mozi engaged in nine simulated war games with Gongshu Ban, the chief military strategist of Chu, and overturned each one of his stratagems. When Gongshu Ban threatened him with death, Mozi informed the king that his disciples had already trained the soldiers of Song in his fortification methods, so it would be useless to kill him. The Chu king was forced to call off the war.
On the way back, however, the soldiers of Song, not recognizing Mozi, would not allow him to enter their city, and he had to spend a night freezing in the rain. After this episode, he also prevented the state of Qi from attacking the State of Lu. He taught that the defense of a city did not depend only on fortification, weaponry, and food supply, but rather that it was also important to keep talented people close by and to put trust in them.