The deba is a classic Japanese culinary knife. Used most often to process fish and poultry, it combines some of the functions of a cleaver with some of the functions of a chef's knife. The deba is used to behead and fillet fish, cut through small bones and skin, bone poultry, and cut meat. This traditional single-bevel design is perfect for medium-sized fish as well as smaller poultry, but many cooks like it for chopping, dicing, or mincing tasks, too. Single-beveled blade.