This chapter assesses the controversy over the knives used in sheḥitah, or slaughtering of animals. In east European Jewish society, meat was a central element of the diet, and the observance of the kosher laws was one of the most obvious ways in which Jews were distinguished from non-Jews. Moreover, a rigorous observance of these laws was one of the ways in which individual Jews demonstrated their piety. The quality of the ḥalaf, or knife used for sheḥitah, is one of the key elements in determining whether meat is kosher or not. During the early days of the hasidic movement, a dispute over the type of knife that should be used — specifically a demand that slaughtering knives be sharpened or ‘polished’ in a special way — played a major role in the struggle between the hasidim and their opponents, particularly the mitnagedim. The decline of this dispute contributed to the establishment of a degree of peace, or at least coexistence, between the groups.