Sanming TonghuiVol. 1, On the Nature and Fortune of the Sixty Jiazi (verdicts & remarks)
Wu Zi Fire is thunder. It delights in Water, spring, and summer, and achieving Earth it displays heavenly spiritual power. Hidden Spirit, Early Demise, Nine Uglies, Cane Punishment, Flying Blade.
In Wu Zi, stem and branch flourish in the north, the position of Water; its Na Yin belongs to Fire, making it Fire within Water, which none but a divine dragon can possess.
In Bing Wu, stem and branch flourish in the south, the position of Fire; its Na Yin belongs to Water, making it Water within Fire, which none but the Heavenly River can possess. When a Wu Zi person obtains Bing Wu, or a Bing Wu person obtains Wu Zi, nobility is unfailing.
For Water is born within Fire and Fire is hidden within Water; with Water and Fire perfectly unified, the movement of spirit is bound to be extraordinary among men.