Indirect Percussion Flaking
Indirect percussion flaking involved removing flakes using a punch: the punch was placed on the platform and then struck, initiating the flake at the desired location. By adjusting the angle of the punch, the stoneworker could very precisely balance the force of compression down the length of the developing flake (‘downward’ force) and the shearing force which opens up the crack (‘outward’ force).
The punch could be adjusted relative to the contours on the core face and placed at precise distances from the core edge. The tip of a punch could also be positioned in places that would be impossible to reach by direct percussion, such as within a concavity on the core edge. An organic punch flexes when it is struck and more slowly releases the force into the core than in direct percussion.
Punches were mostly made from antler, although horn, bone, or wood may have also been used. Modern flintknappers have successfully used stone punches to shape rectangular-sectioned adze blanks. Indirect percussion arose relatively late in prehistory but was discovered independently in various times and places.