Drichu

Ü (dbus) - 1) center, middle, midst, amidst, core, central. 2) Central Tibet, a district in Tibet; Ü One of the two central provinces of Tibet, the other being Tsang. (gtsang). [RY]

From The Light of Wisdom, vol. 1, pg. 239, Note 134: For details of places Ngari (stod mnga' ri) and Dokham (mdo khams): Mount Tisey surrounded by snow mountains, Gugey surrounded by slate mountains, and Purang surrounded by water are the Three Districts of Ngari in Upper Tibet, which were formed in the manner of a pond. Lharu and Geru in Tsang (gtsang) and Yeru and Yönru (g.yon ru) in Central Tibet are the Four districts of Ü and Tsang in the middle, which were formed in the manner of an irrgation channel. The Six Ridges are Zalmo Ridge, Tsawa Ridge, Markham Ridge, Menyag-rab Ridge, Pobor Ridge, and Mardza Ridge. The Four Rivers are Manchu, Dzachu, Drichu, and Ngulchu. These are the Six Ridges and Four Rivers of Lower Dokham, which were formed in the manner of a plough furrow. Thus it has been told.

It is also said that the Three Districts of Ngari in Upper Tibet in the manner of a warrior's battle axe, the Four Districts of Ü and Tsang in the middle were formed in the manner of a precious gold belt, and the Six Ridges and Four Rivers of Lower Dokham were formed in the manner of a beautiful lining of plush silk. (JOKYAB)