Abstract
<jats:p>This paper presents the results of a techno-typological and statistical analysis of assemblages from key Middle Palaeolithic layers (12.1, 12.3, 17) at the Kulbulak site. The study aims to determine their position within the Obi-Rakhmatian and to elucidate the nature of its long-term developmental trajectory. Based on the study of 8,790 artifacts and the application of non-metric multidimensional scaling (NMDS), a detailed comparison was conducted between the Kulbulak assemblages (layers 12.1, 12.3, 17) and both chronologically earlier (Kulbulak layers 23–24) and later (Obi-Rakhmat layers 17–21) industries. The results demonstrate that the assemblages from the middle part of the Kulbulak sequence (~89–120 ka) fall within the single variability range of the Obi-Rakhmat variant across all key parameters (debitage structure, core types, and tool composition). They thereby fill a significant chronological gap between its earliest (~200–180 ka) and latest (~85–40 ka) phases. It is shown that, despite variability influenced by raw material and possibly functional factors, the Obi-Rakhmatian is characterized by a remarkable stability in its core techno-typological characteristics from the late Middle through the end of Middle- first half of the Upper Pleistocene, exhibiting no evidence of directed linear development.</jats:p>