Nàng Han is the warrior-maiden of Tai tradition in the Northwest, a heroine sometimes likened to a Joan of Arc of the Tai. In the legend she disguises herself as a man to rally the Tai of the upper Black River and the Nậm Na and drives back a northern invasion; her victory secured, she bathes at a spring and vanishes, and thereafter she is venerated as a tutelary spirit. Her cult persists in an annual festival, the Lễ hội Nàng Han, held in Tai communities of Lai Châu and Sơn La (notably Quỳnh Nhai and Mường So), where offerings and communal dances renew her protection of the mương.