The Xiazhai site is located to the north of Xiazhai village in Taohe Township, Xichuan County, Nanyang City, Henan Province. From 2008 to 2013, the Henan Provincial Institute of Cultural Heritage and Archaeology carried out continuous exploration and excavation work. The site harbors cultural remains spanning from the Yangshao period, through the Shijiahe culture period, the late stage of the Wangwan-III culture, the early Erlitou period, the Western Zhou period, the Eastern Zhou period, all the way to the Han, Tang, and Ming-Qing dynasties. Among these, a particular type of stone flakes with distinctive technological traits were unearthed from the Neolithic and Eastern Zhou cultural layers, as well as from pits and other archaeological contexts. After careful observation and in-depth analysis of these flakes, this study proposes that they were probably fabricated using the ridged-hammer bipolar flaking technique.

The ridged-hammer bipolar flaking represents a modified version of the Bipolar technique. Its technical crux lies in employing a stone hammer with a flat and sharp edge to execute an oblique, downward blow to the lateral edge of a flat stone core. Currently, while domestic scholars in China have engaged in extensive discussions regarding the ridged-hammer bipolar flaking technique, international counterparts have yet to acknowledge it as an independent flaking methodology. Some scholars contend that there is no essential disparity between ridged-hammer bipolar flakes and those generated by hammerstone percussion, sparking debates over the identification features, application modalities, and purposes of the ridged-hammer bipolar flaking technique.

This paper offers a concise review of the research history and extant issues related to the ridged-hammer bipolar flaking technique. By integrating prior research and experimental observations, identification criteria for the products of this technique have been distilled, taking into account elements such as flake butt, strike point, flaking angle, and the morphology of both the dorsal and ventral surfaces. Subsequently, these criteria are applied to identify and conduct quantitative and qualitative analyses of the ridged-hammer bipolar flakes unearthed at the Xiazhai site.

By scrutinizing the residual technological characteristics of ground stone tool blanks and the grinding marks on the dorsal surface of the ridged-hammer bipolar flakes from the Xiazhai site, this paper dissects the position and function of the ridged-hammer bipolar flaking technique within the operational sequence of ground stone tool production. The spatio-temporal distribution of sites where ridged-hammer bipolar flaking products were uncovered indicates that regions where this technique prevailed during both the Paleolithic and Neolithic periods were rich in stone materials and hunting and fishing resources. Significantly, at the Xiazhai site, the ridged-hammer bipolar flaking technique was not only utilized to procure flakes but also played a crucial part in the grinding and manufacturing process of ground stone tools, furnishing valuable insights into the inheritance and evolution of lithic technology.