According to the legend, emperor Lê Lợi handed a magic sword called Heaven's Will which brought him victory in his revolt against the Chinese Ming Dynasty back to the Golden Turtle God (Kim Qui) in the lake and hence gave it its present name (the lake was formerly known as Luc Thuy meaning "Green Water"). The Turtle Tower (Thap Rùa) standing on a small island near the centre of lake is linked to the legend.
Turtle Towe
The tower was erected on the Turtle islet, the former fishing site under king Le Thanh Tong.[Under the Restored Le Dynasty (17th and 18th centuries), the Trinh Lords had Ta Vong Temple built on the islet, which disappeared during the Nguyen Dynasty. After the French conquered the Hanoi Citadel, most of the population around the lake fled away. Vietnamese officials also fled their offices. There stayed only Nguyen Ngoc Kim, who was the mediator between the French troops and the Vietnamese.
Large soft-shell turtles, either of the species Rafetus swinhoeior a separate species named Rafetus leloii in honor of the emperor, have been sighted in the lake. The species is critically endangered and the number of individuals in the lake is unclear. Near the northern shore of the lake lies.