From the Matsang Tsangpo-Phung Chhu divide, the Matsang flows directly south into Nepal where its name changes to Sun Kosi. North of the divide Men Chhu flows northeast into the Phung Chhu (or Bum Chhu in Tibetan; Peng Qu in Chinese) which flows east to 87d40'E where it combines with other streams and turns south to cut a deep valley between the Mahalangur (Mount Everest) and Kanchenjunga sections of the Himalaya. As it crosses into Nepal its name changes to Arun. Sun Kosi and Arun are both counted among the Kosi River's seven notable Himalayan tributaries.