Chinese metaphor in Buddhism and Daoism
Shengtai (聖胎, "sacred embryo" or "embryo of sagehood") is a Chinese syncretic metaphor for achieving Buddhist liberation or Daoist transcendence. The circa fifth century CE Chinese Buddhist Humane King Sutra first recorded shengtai ("sagely womb") describing the bodhisattva path towards attaining Buddhahood; shengtai was related with the more familiar Indian Mahayana concept of tathāgatagarbha ("embryo/womb of the Buddha", Chinese rulaizang (如來藏) that all sentient beings are born with the Buddha-nature potential to become enlightened. The Chan Buddhist teaching master Mazu Daoyi (709-788) first mentioned post-enlightenment zhangyang shengtai (長養聖胎, "nurturing the sacred embryo"), and by the tenth century Chan monks were regularly described as recluses nurturing their sacred embryo in isolated locations. The renowned Daoist Zhang Boduan (984-1082) was first to use the expression shengtai ("sagely embryo") in a context of physiological neidan Internal Alchemy, and neidan adepts developed prolonged meditation techniques through which one can supposedly become pregnant, gestate, and give birth to a spiritually perfected doppelganger.
