An anvil for a surgical stapler. The anvil includes a staple-forming undersurface that has lines of staple-forming pockets that are configured to establish a flexible staple line. A plurality of anvil protrusions protrude from planar non-forming surface portions such that each anvil protrusion is adjacent to at least two staple-forming pockets to direct staples therein during a staple firing process and to engage the tissue that is being stapled.