A correspondent writes: “I have come across a reference to a location in Hong Kong called ‘Temple of Jade Vacuity’ on Cheung Chau island. Googling doesn’t explain it,… though one reference refers to ghosts, and I wondered if that was the ‘Vacuity’ element, and there are other references to Vacuity in Daoist religion (philosophy?).” A little rummaging around Google Books turned up the information that one of the Taoist gods is “Celestial Venerable of Jade Vacuity” (Yü-hsü ming-huang t’ien-tsun/Yuxu minghuang tiancun). I’m guessing the hsü (xu) ‘vacuity’ is Mathews’ character 2821 hsü “False; untrue; unreal. Hollow; empty. Vacant; insubstantial; figurative; abstract.” There are a bunch of other hits for “Jade Vacuity,” and it’s clearly a Taoist thing, but damned if I know what. As I told my correspondent, “I’ll post about it—surely one of the Varied Readers will know.” So: what’s with the odd collocation Jade Vacuity?