A rock guard for use on a rotary disc cutterbar having quick-release knife connectors wherein a knife removal relief channel is oriented 45 degrees from a straight-ahead orientation to allow more than one quarter of the knives on the cutterbar to be simultaneously aligned with the channels for removal. A second knife removal channel is also oriented 45 degrees from the straight ahead orientation and 90 degrees from the first channel to permit half of the knives on the cutterbar to be simultaneously aligned with the channels for removal. The incorporation of two knife removal channels as described benefits rotary cutterbars having two knives per rotary cutter and adjacent cutters rotationally offset by 90 degrees regardless of whether co-rotating or counter-rotating rotary cutters are employed.