Naviform (Bidirectional) Blade Core Reduction with commentary by Chris Clarkson

This is a typical Upper Palaeolithic/Neolithic blade core reduction strategy. It begins by setting up a 'boat shaped' core (hence the term naviform), with a large crested ridge down the front of the core and two obliquely angled platforms at the back on opposite ends of the core. This kind of core, once properly set up, is very self-maintaining, requiring only occasional platform rejuvenations which are simple and easily accomplished and almost no rectification of the core face as steps and hings are removed from opposite ends. The slight core face curvature created by bidirectioanl flaking also helps to reduce or even completely eliminate step terminations. This technology yields distinctive pointed and hollow ended blades with bidirectional scar patterns, the best of which are very wide with very flat ventral surfaces, making them ideally suited to the manufacture of large points and sickle blades. A very large number of blades can be manufactured from these cores, as seen from refits of ancient cores from famous quarries, including the Golu Dag obsidian quarry in Central Anatolia and from Israel. See Wilke and Quintero 1995 Paleorient, and Barzilai and Goring-Morris 2013 Journal of Archaeological Science, for further replicative and archaeological examples and discussion.