In a bulk bin having side walls joined to one another at adjacent edges along vertical scores, and bottom flaps joined to bottom edges of the side walls along a flap score, with adjacent flaps separated from one another by a flap slot, a shaped cut is made at the terminal end of the flap slot to redirect stress away from the bottom end of the vertical score and resist initiation of tearing of the vertical score at that point. In one embodiment, the shaped cut is a downwardly open hook shape which terminates in an end pointing laterally away from the vertical score and into the flap. In another embodiment, the shaped cut resembles a modified Greek letter psi (.psi.), with the ends pointing laterally away from the vertical score, and in still another embodiment, the shaped cut is "T" shaped, with the ends of the "T" pointing laterally away from the vertical score.