Detail: Guan yao, the fabled ‘official ware’ specially created for the imperial court of the Southern Song in Hangzhou in south China, is perhaps the most desirable and certainly one of the rarest types of Chinese ceramics. The exquisite, unctuous glaze of the present vase, suffused with a distinct web of veins of the large-scale crackle, gives the whole piece an aspect as if carved out of one large boulder of a fine jade-like stone. Although this crackled bluish-green guan ware became one of China's most widely admired and most avidly imitated ceramic styles, actual examples are exceedingly rare even in the Palace Museums of Taipei and Beijing, since despite the expertise of the craftsmen, a satisfactory outcome was rare even at the time.