The 9th day of the 9th lunar month doubles the ultimate yang number, creating the year’s most concentrated pure yang energy at a time when yin is otherwise ascending. Climbing mountains on this day is not merely tradition but a Taoist practice of ascending toward heaven’s yang qi to counterbalance the encroaching yin of autumn. Chrysanthemum wine, infused with the flower that blooms when all others die, carries the essence of immortality. Wearing dogwood (zhuyu) repels evil qi. The I Ching’s hexagram 1, Qian (Pure Yang), resonates on this double-nine day.