In the earliest extant specialist medical work sMan dpyad zla ba’i rgyal po (The Medical Investigation of the Lunar King, early 8th century CE) and the classical work of Tibetan medicine, rGyud bzhi (The Four Medical Tantras, generally dated by scholars to the 12th century CE), there are records of rtsa in its meaning of 'pulse taking'. The concept of rtsa in Tibetan medicine, as the Chinese mai脈, eventually came to combine notions of 'the vessels' and 'channels' of the body with diagnostic readings of 'pulsating vessels' at its surface. This article considers the earliest extant records of rtsa from Dunhuang and finds evidence of the separate development of these two aspects. These early records are unique inasmuch as they not only provide a source for history of medicine, but also represent Tibet and Tibetan culture as an important place for both cultural exchange and resistance, particularly in the transmission of medical knowledge and practice from China.