Sanming TonghuiVol. 1, On the Nature and Fortune of the Sixty Jiazi (verdicts & remarks)
Gui Wei Wood represents the willow's roots; it delights in winter and Water, and is likewise suited to spring. Direct Seal, Canopy, Early Demise, Hidden Spirit, Flying Blade, Broken Character. Gui Wei is Self-Storage Wood.
It is fine when flourishing and engendered; even Yi Chou Metal cannot shatter it, as each returns to its own root without encroaching upon the other. It dreads Geng Xu and Yi Wei Metal.
The Jade Night Precious Mirror says: "Ren Wu and Gui Wei are called Willow Wood because Wood dies at Wu and enters its tomb at Wei; hence its foliage is dense in midsummer. Met in its proper season, it brings wealth and longevity; out of season, poverty and premature death."