According to legend, the sword was given to Lê Lợi by the turtle god, Kim Quy. The sword possessed magical power, which supposedly made Lê Lợi grow very tall. When he used the sword it gave him the strength of a thousand men. After Lê Lợi was successful in establishing an independent kingdom, while out on a boat on a lake, Kim Quy jumped out of the water, grabbed the sword, and disappeared underwater. The lake now bears its namesake, Hoàn Kiếm Lake, or literally the Lake of the Returned Sword.
Some versions of the story say the entire sword was given by Kim Quy, while other versions say only the hilt was given by Kim Quy and that Lê Lợi found or forged the blade on his own.