The Paleolithic people made stone tools out of many materials, but one of the most valued among materials was obsidian, a glassy volcanic rock that is usually black but that can be dark brown or reddish brown.
Obsidian breaks cleanly with sharp edges so it was prized for making axe blades and spear heads, and in the following Jomon era, arrow heads. Weapons made of obsidian flakes cut well and deep into animals the hunters caught and also made useful knives for cutting meat, skins and the bark of trees.
Obsidian tools from the Paleolithic era (Kawasaki City Museum)
In fact, obsidian was so treasured the Paleolithic people went to great lengths to obtain their obsidian.
Using X-Ray Fluorescence analysis, experts knew that some of obsidian stones found in the Doteue site in Numazu City, Shizuoka prefecture came from the Kozu Island in the Sagami Bay. As far back as 30,000 years ago, the Paleolithic people had to cross the waters from the mainland to get to the island of Kozu which was their source of obsidian. They took great risks to obtain a chunk of rock! The fact also tells us they got across in some kind of water vehicle, possibly a raft or a dugout. Oki obsidian artifacts were found on the coast of Russia in the 10,000 year-old Vladiovostock and Navatoka. This means the Paleolithic people between Japan and Russia ventured far and across the sea and continent to exchange or trade for the rock.
From as early as 20,000 years ago, obsidian was being traded over distances of 150 kilometres. Much of that trade took place over water so it’s a safe bet they were using watercraft back then. There are about 60 known sources of obsidian rock in japan today although not all sources were discovered by the Paleolithic people, see map here.
The Paleolithic people made large and rough core tools by working on a fist-sized piece of rock (called the core) with a similar rock (called the hammerstone) and knocking off several large flakes and chipping away the surface of a stone. They also produced flake tools by working with a stone flake broken off from a larger piece of stone. The stone tools are like the “signature” or “footprints” left behind by the Paleolithic people, and the various tools that were produced include trapezoids, edge-ground stone axes, backed-blades, leaf-shaped bifacial point-tools, pebble tools, grinding and pounding tools, and microblades (tools with blades smaller than 1 centimeter).
Paleolithic stone tools (Kawasaki City Museum)
Wherever Paleolithic people made their base campsites, they left behind traces of many small flakes and chips from the manufacture and maintenance of stone tools. Even at their work camps and butchering sites, and temporary sites, they would have left lots of stone flakes and chips – the telltale signs of tool sharpening. And that’s what archaeologists look out for when they go digging in search of Stone Age finds. Only a few tools made of bone have been found.
Another material popularly used for making stone (core and flake) tools was black and glassy andesite from lava flow layers of the central Japan area.