Grb is the longest river in Tak. For a large part it forms a natural border with Bowdani. Its source can be found in the mountain range in north-central Tak. It flows through the cities of ƿɛVii Gɛk, Ɣoot Nnt, Vit, from Ag along the Bowdani border to Grg, where it is interrupted by Pearyt Lake, after which it continues its course from Tək, along the Bowdani border. Shortly after Fɛl rd Boot it turns away from the Bowdani border, it passes Hoop, and in Lp it flows into the Dark Sea. Between Tək and Lp, Grb is navigable.