 At its headwaters in the Letha Mountains (Letha Tang) of Tonzang Township in Chin State it is known as the Tuimi Lui.It flows off the slopes of Mount Wapit (Wapit Vum) () and Mount Nauko (Nauko Vum) ().It is joined by the Tuilam Lui from the right (west) and the Lauthu Lui from the left (north) and becomes the Neyinzaya below Leikan, as it flows into the Kale Valley and into western Sagaing Region.