Vacuity is a term which is germane to the Kidneys. The terms Kidney Qi vacuity, Kidney Yin vacuity, and Kidney Yang vacuity, all describe a state of emptiness or depletion. Qi is vacuous when there is a lack of accumulation of it. Words such as “deficiency” and “weakness”, commonly used as translations in the West, convey a sense of qualitative fragility not implied by the Chinese term “xu”, meaning vacuity.