“Golden flower,”
The Secret of the Golden Flower
The Secret of the Golden Flower was first translated into German by sinologist Richard Wilhelm, a friend of Carl Jung, who had been introduced to the work by his Chinese teacher.[17] The work was later translated from German to English by Cary F. Baynes.[18] Jung provided comments to both of Wilhelm's major Chinese translations, including (in 1949) the nineteen-page (pp. xxi–xxxix) foreword to the Wilhelm/Baynes translation of the I Ching, discussing the transpersonal aspect, and The commentary on The secret of the golden flower (1929).
See "The Golden Castle" mandala by Jung

