What is Shouyi "守一" in Taoism?

Shouyi "守一" is a Taoist cultivation technique, which refers to the internal practice method of maintaining the soul, spirit, or essence, qi, and spirit within the body, so that they do not escape outward but remain in the body.

Taoism believes that when the form and spirit are united, there is life; when the form and spirit are separated, there is death. In order to keep the body intact and achieve immortality, cultivators must abandon desires and greed, cut off the channels through which the soul and spirit run outward, and make them stay in the body for a long time. The spirit is formed by the condensation of essence and qi.

 In order to prevent the spirit from escaping, it is necessary to nourish the essence and qi for a long time, so that they do not leak or escape, and integrate with the spirit. Shouyi (guarding the one) is an early Taoist technique. After the Sui and Tang Dynasties, it gradually merged with techniques such as Qixing (breathing exercises) and Daoyin (physical guidance) and evolved into Neidan (internal alchemy).