According to traditional Chinese medicine, the kidney (Chinese: 腎: shèn) refers to either of the two viscera located on the small of the back, one either side of the spine. As distinct from the Western medical definition of kidneys, the TCM concept is more a way of describing a set of interrelated parts than an anatomical organ. In TCM, the kidneys are associated with "the gate of Vitality" or "Ming Men". A famous Chinese doctor named Zhang Jie Bin (approximately 1563-1640) wrote "there are two kidneys, (kidney yin and yang), with the Gate of Vitality between them. The kidney is the organ of water and fire, the abode of yin and yang, the sea of essence, and it determines life and death."