Pebble tools (礫石器)
Pebble tools are the stone tools made of rude ore that have not been processed. These include throwing stones as hunting tools or weapons, mill stone for flour milling or cooking, hammer or concave stone for cooking, grinding stone for polishing, and so on. Basically the criterion to determine whether a stone was a stone tool or not is to check whether there is a use-wear or not. However, since ore is used as tools as it is, it is often difficult to determine whether it was a relic (archaeological materials) or not. In these cases it is essential to consider whether or not there were accompanying relics such as stone plates, as well as the excavated structural remnants and excavation state. In addition, it should be noted that pebble tools are different from chopping tools which are primitive stone tools.