The earliest stages of the MSA show the emergence of a number of technical innovations accompanying the appearance of uni-bifacial pointed tools that are the hallmarks of this period. Within the oldest sites of Gademotta and Kulkuletti, a specific technical process applied on convergent tools has been identified: the lateral tranchet blow technical process. This paper questions the value of this process in terms of technical skills and functional purpose and to a broader extent, its value as a chrono-cultural marker. The first clue of this study is to provide an accurate evidence of the intentionality of the tranchet blow process based on the identification of the recurrent technical stages implied in this process. With regards to the study of the emergence of projectile technology in the literature, the morpho-functional significance of this process is also questioned. The hypothesis supported in this paper favor the interpretation of the use of the tools with tranchet blow scars as cutting tools rather than hunting weapons. Therefore, the penetration function of those MSA triangular tools may precede their function as projectile. The discussion shows that, so far, the use of the tranchet blow process was restricted to the oldest sites of Gademotta and Kulkuletti. Since it has been recognized in Tiya surface collections, this process may be considered as a chrono-cultural marker for the Ethiopian MSA.