In various embodiments, a stapling assembly is disclosed. The stapling assembly comprises, among other things, an anvil configured to deform staples. The anvil comprises a tissue-engaging surface and a pair of forming pockets defined in the tissue-engaging surface, wherein the pair of forming pockets are configured to deform corresponding legs of a staple. The pair of forming pockets comprises a proximal forming pocket and a distal forming pocket. Each pocket comprises a forming surface, wherein the forming surface comprises an entry zone comprising a first radius of curvature and an exit zone comprising a second radius of curvature, a pair of sidewalls extending at an angle from the forming surface toward the tissue-engaging surface, and a groove defined in the forming surface, wherein the groove comprises a diameter which is less than a wire diameter of the staple.
