6,300 km. The longest river in Asia and China, and the third-longest in the world. Like many rivers, the river is known by different names over its course. At its source it is called in Chinese the Dangqu. Downstream it is called the Tuotuo River and then the Tongtian River. Where it runs through deep gorges parallel to the Mekong and the Salween before emerging onto the plains of Sichuan, it is known as the Jinsha River.