Yu the Great (Chinese: 大禹; pinyin: Dà Yǔ, c. 2200 - 2100 BC), was a legendary ruler in ancient China famed for his introduction of flood control, inaugurating dynastic rule in China by founding the Xia Dynasty, and for his upright moral character.

Few, if any, records exist from the period of Chinese history when Yu reigned. Because of this, the vast majority of information about his life and reign comes from collected pieces of oral tradition and stories that were passed down in various areas of China, many of which were collected in Sima Qian's famous Records of the Grand Historian. Yu and other "sage-kings" of Ancient China were lauded by Confucius and other Chinese teachers, who praised their virtues and morals.

Yu is one of the few Chinese rulers posthumously honored with the epithet "the Great".

Great Yu Controls the Waters

During the reign of King Yao, the Chinese heartland was frequently plagued by floods that prevented further economic and social development. Yu's father, Gun, was tasked with devising a system to control the flooding. He spent more than nine years building a series of dikes and dams along the riverbanks, but all of this was ineffective, despite (or because of) the great number and size of these dikes and the use of a special self-expanding soil. As an adult, Yu continued his father's work and made a careful study of the river systems in an attempt to learn why his father's great efforts had failed.

Collaborating with Houji - a semi-mythical agricultural master about whom little is concretely known - Yu successfully devised a system of flood controls that were crucial in establishing the prosperity of the Chinese heartland. Instead of directly damming the rivers' flow, Yu made a system of irrigation canals which relieved floodwater into fields, and spent great effort dredging the riverbeds. Yu is said to have eaten and slept with the common workers and spent most of his time personally assisting the work of dredging the silty beds of the rivers for the 13 years the projects took to complete. The dredging and irrigation were successful, and allowed ancient Chinese culture to flourish along the Yellow River, Wei River, and other waterways of the Chinese heartland. The project earned Yu renown throughout Chinese history, and is referred to in Chinese history as "Great Yu Controls the Waters" (Chinese: 大禹治水). In particular, Mount Longmen along the Yellow River had a very narrow channel which blocked water from flowing freely east toward the ocean. Yu is said to have brought a large number of workers to open up this channel, which has been known ever since as "Yu's Gateway" (Chinese: 禹門口).

Apocryphal stories

In a mythical version of this story, presented in Wang Jia's 4th century AD work Shi Yi Ji, Yu is assisted in his work by a yellow dragon and a black turtle (not necessarily related to the Black Tortoise of Chinese mythology). Another local myth says that Yu created the Sanmenxia "Three Passes Gorge" of the Yangzi River by cutting a mountain ridge with a divine battle-axe to control flooding.

Traditional stories say that Yu sacrificed a great deal of his body to control the floods. For example, his hands were said to be thickly callused, and his feet were completely covered with callus. In one common story, Yu had only been married four days when he was given the task of fighting the flood. He said goodbye to his wife, saying that he did not know when he would return. During the 13 years of flooding, he passed by his own family's doorstep three times, but each time he did not return inside his own home. The first time he passed, he heard that his wife was in labor. The second time he passed by, his son could already call out to his father. His family urged him to return home, but he said it was impossible as the flood was still occourring  on. The third time Yu was passing by, his son was over 10 years old. Each time, Yu refused to go in the door, saying that as the flood was rendering countless numbers of people homeless, he could not rest.

Yu was supposed to have killed Gong Gong's minister Xiangliu, a nine-headed snake monster.