Abstract: Although the wedge-shaped core has been regarded as an indicator of transcontinental cultural connections about half a century, studies on this kind of microblade cores have been limited to its static morphology. This has resulted in a lot of problems in the understanding of the nature of the cores and of using them for regional comparison of Paleolithic cultures. Trying to clear some of these problems, it is intented to apply the dynamic typology to a study of the microblade cores from Hutouliang Upper Paleolithic site, Yangyuan county, Hebei Province, North China. Such a study focuses on the identification of the technological chain of the manufacturing process of the cores. It is considered that the dynamic typology of micro-cores will throw more light on their classification.
79 pieces of spalls, core preforms and cores, made of silicalite, are examined for the study.
The characteristics of Yan^yuan core are：
1) There is a fluted surface in the front of the core; One of the lateral surface of the core is convex and the opposite surface is flat, so that the core is D-shaped in cross section ；
2) The platform is flat or beveled to the convex lateral surface of the core;3) With the removal of the microblades the core's shape alters from oval to waterdrop-like.
4) A distinct technological chain of manufacturing process of Yangyuan core is reconstructed and two sub-types of Yangyuan core are subdivided. The technological process is described below
Phase 1
Manufacture of oval core preforms for the two sub-types ；
Phase 2
Retouching the edges of the core preform for the sub-type 2, or making a stop notch on the upper edge of the core preform for the sub-type 1;
Phase 3
Forming the platform of the core by removing the spall (s) which stop (s) at the notch or the upper edge for the stub-type 1, or rejuvenatiog the platform in the process of microblade production for the sub-type 2;
Phase 4
Removing the mieroblades. In the ease of the sub-type 2 of Yangyuan core the alteration of the position of the core fixed for producing the microblades occurs, and the change of the shape of the cores takes place gradually.
The technological mechanism of microblade production and the construction ideas of the core manufacture are traced and discussed on the observations of Yangyuan core. It is fascinating that the Yangyuan core finds its counterpart as Togeshita mie- roblade core from Hokkaido, Japan. The interesting relation between them will be dealt with in a forthcoming paper.

Key words: Hutouliang Upper Paleolithic site; Yangyuan core; Dynamic typology of micro-core; Analysis of technological ideas