“A method of producing a transverse fracture to sever flakes or blades. Pressure or percussion force is applied from the ventral toward the dorsal side" (Crabtree 1982., 53).
Normally undertaken to reduce the size, or remove unwanted sections, of an artifact (such as the bulbar end or the distal end). This is surprisingly difficult to accomplish directly by hand with any degree of accuracy (Owen 1982, 78-79). ​ ​ Either a hard hammer or soft hammer can be used. This leaves characteristic features of a normal detachment, such as a bulb, lines of force, etc. (Owen 1982,, Roche and Tixier 1982).