A short distance south of the Stone Fortress, a separate ridge holds the ruins known locally as the Princess Castle (Gongzhubao). The legend, recorded by Xuanzang and still told to visitors, has a Han Chinese princess sent west to marry a Persian prince, stranded here when the road closed, and impregnated by a sun god. Her son founded the Sarikol kingdom. Whatever you make of the story, the ridge has commanding views and is an easy 30-minute walk from town.
The remains are minimal — a few stone foundations and the outline of a small enclosure — and not really the point. The walk up the ridge and the panorama across to the Stone Fortress and the grasslands beyond are. On a clear day Muztagh Ata's white cone shows on the eastern horizon. Go in the late afternoon when the light hits the fortress walls.