The invention provides a perforation cutting rule for a rotary cutting machine and method of operating the same. The cutting rule has a length, height and thickness and includes a plurality of dovetail-shaped gaps formed along a longitudinal edge to define a plurality of dovetail-shaped cutting teeth. Each tooth includes an outer cutting end and an inner base end, the outer cutting end having a length greater than an inner base end. As the cutting end cuts through multiple sheets the angled sides of the dovetail-shaped teeth provide a relief area to prevent the sheets from bunching or pulling against the teeth during the cutting operation.