Abstract: A perforating blade and signature having a unitary blade (12) that is very narrow in width in proportion to its length, with a cutting edge (16) along one longitudinal side. The cutting edge (16) comprises a combination of a number of spaced-apart straight (12) and angled (20) sections arranged so that the angled sections (20) angle inwardly toward a center point (18) on the perforating blade and along a single side of the cutting edge only. In one embodiment the pattern starts with a single long cutting tooth in the center (18) of the blade followed outwardly from the center on both sides with a repeating pattern of three angled teeth followed by a short straight tooth and so forth. The angled teeth (20) are all angled to the same side of the blade so that the resulting fold line (26) has cuts only on one side (29) of the fold line. The angled cuts result in ties (28) that twist easily, and that, therefore, result in fold lines (26) that fold cleanly without gusseting or binding.