The Art of Strengthening Yin is one of the most important, but at the same time rare, Taoist practices aimed at collecting and strengthening energy for the subsequent strengthening of the alchemical process. This practice is most common among women, but is also practiced by men who have impaired natural energy circulation. This tradition is presented according to the teachings of the school of the Nine Heavenly Mentors, which has its origins in the Maoshan tradition. About all this and not only in the book The Art of Strengthening Yin (Jie Kun).