Willow is the 24th constellation of the 28 mansions and is made up of eight stars. It is the head of Hydra.

Since the Han dynasty, there has been a custom in Chang'an of escorting people going on long journeys to the foot of the bridge and breaking off willow branches growing there as a farewell gift. Willow branches are flexible and bend easily, and even if bent, they return to their original shape, so they were used as a good luck charm to ensure a safe return from the journey.

In China, willows are considered to be one of the sacred trees in which spirits reside. In the loess region of Hebei, willows sprout earlier than other plants, and because of their flexible and strong nature, they were believed to have the power to ward off evil. There is also a teaching that says, "If you take a willow branch and place it on your door on New Year's Day, no demons will enter your house," and there was also a custom of offering it near graves.

According to an old legend, the sun leaves our country of Fuso at dawn and enters the thin willow tree in the west at dusk every day, and mulberry trees and willow trees are said to be at the ends of the earth in the east and west, where the sun and moon rise and set. The Willow Tree of the 28 Mansions is said to be likened to the beak of the Vermilion Bird, which protects the south.