Table 6. Shizitan 29: The reduction sequence.

	Black flint	River flint	Quartzite
Stage A	This stage is not observed. Probably Black flint is imported into the site as pre-formed cores or as large, thick flakes to be used as cores.	Pebbles may be splitted by means of anvil percussion or, more probably, by detaching a large thick flake by means of direct percussion. The flake and the residual pebble may both be used as a blade core.	Pebbles may be splitted by means of anvil percussion or, more probably, by detaching a large thick flake by means of direct percussion. The flake and the residual pebble may both be used as a core.
Stage B	The core is used, or the ventral surface of a flake is used as the striking platform, each of which has very little—if any—preparation throughout the knapping sequence. By direct percussion, unidirectional elongated flakes are produced so as to shape the core in order to obtain a pre-formed blade core. From this stage, the core may also be exploited in order to produce only flakes or elongated flakes; in this case the reduction sequence may continue until Stage D.		Flake production by direct percussion (or even by anvil percussion) to exploit the core until its abandonment.
	The natural morphology of Black flint (squared blocks or irregular nodules) requires a more developed preparation. Preparation includes flakes or elongated flakes that are detached from any side of the core. This provides an angulated side to the core that will be exploited for the beginning of the blade production.	The natural morphology of River flint (rounded pebbles) does not require a more developed preparation
Stage C	The production of blades starts. No maintenance of the core is needed. The core is abandoned at this stage only when completely exploited or because of knapping mistakes. The blades are usually detached from one side of the core: this mainly allows the production of blades with a straight profile.
	Maintenance of the core is more complex when Black flint is knapped. Following the natural morphology of the core, several technical products must be occasionally detached in order to continue the blade production. These include blades with a naturally backed edge and flakes or elongated flakes from different areas of the core: their removal keeps the working surface as large as possible, provides crests, and so on.	The natural morphology of River flint (rounded pebbles) does not require a complex maintenance of the core
Stage D	When blade production is over, but the core is not completely exhausted, it can be exploited by direct percussion (less probably by means of anvil percussion) to produce more flakes. Similarly, flake cores can reach this stage directly from Stage B.

Description of the reduction sequence stages for the Black flint, River flint, and quartzite at Shizitan 29