This is a version of the yin-yang symbol or Taijitu (太極圖) often used by Taoist internal alchemists. In the traditional Taijitu, the hot, bright, white yang nature rises while the cold, dark, black yin nature descends. Taoist esoterics will often invert the symbol because they believe in this configuration the heat from the yang will be able to cook the jing in the yin producing qi which leads toward longer life and immortality.
Own work
Kenny Shen