The Yu Dynasty existed. The Yu Dynasty (about 36th century BC - about 21st century BC), also known as the Yellow Emperor Dynasty, was a dynasty in Chinese history that may have existed for thousands of years. Before the Xia Dynasty, Qi was the last ruler of the Yu Dynasty.
In ancient Chinese history, the world generally calls the Xia, Shang, and Zhou dynasties, but some ancient books call them the Yu, Xia, Shang, and Zhou dynasties