Chinese porcelain and the material taxonomies of medieval Rabbinic law: encounters with disruptive substances in

This article focuses on a set of legal questions about sini vessels (literally, "Chinese" vessels) sent from the Jewish community in Aden to Fustat (Old Cairo) in the mid-1130s CE and now preserved among the Cairo genius holdings in Cambridge University Library. This is the easiest dated and localised query about the status of sini vessels with respect to the Jewish law of vessels used fr food consumption. Our analysis of these queries suggests that their phrasing and timing can be linked to the contemporaneous appearance in the Yemen of a new type of Chinese ceramic ware, qingbai, which confounded and destabilised the material taxonomies underpinning rabbinic Judaism. Marshalling evidence from contemporary Jewish legal compendia and other writings produced in this milieu, our discussion substantially advances interpretive angles first suggested by S.D. Goitein and Mordechai A. Friedman to examine the efforts of Adeni Jews to place this Chinese ceramic fabric among already legislated substances, notably the "neighbouring" substances of glass and earthenware, in order to derive clear rules for the proper use and purification of vessels manufactured from it.