Ring-shaped block group (from the south) Approximately 30 m in diameter, compared with other examples it can be called medium in scale. The circle in the photo is Block 4.	Central portion, where knife-shaped stone blades and carbonized materials were found In Block 4, corresponding to the central portion of the ring-shaped block group, stone tools thought to have been attached to the ends of spears were collectively discarded in broken condition.
Knife-shaped stone blade with discernible flaking from impact Recovered from a locus of concentrated stone tools in Block 4. A tool that was attached to the end of a spear, a trace mark is left from thrusting some object (arrow).
How the stone tools were found   Tools were distributed in the shape of a ring, centering on Block 4. It can be seen that stone tools thought to have been attached to the tips of spears were discarded in concentrated fashion at the center, while items such as stone axes and pebble tools were recovered from the perimeter of the block group. Adapted from Hakkutsu sareta Nihon rettō 2014 [Excavations in the Japanese Archipelago, 2014] (Bunkachō [Agency for Cultural Affairs], ed., Asahi Shimbun Publications, 2014).	A site atop a tableland with a good view (from the south)   There are 31 sites from the Paleolithic through the Ancient periods concentrated on the Goshono tableland where the site lies. Jizōden has been designated a Historic Site because it also has valuable remains of a Yayoi period settlement, and is preserved as a historic park. Adapted from Hakkutsu sareta Nihon rettō 2014 [Excavations in the Japanese Archipelago, 2014] (Bunkachō [Agency for Cultural Affairs], ed., Asahi Shimbun Publications, 2014).

Jizōden Site, Akita City, Akita Prefecture

A ring-shaped block group from the start of the Upper Paleolithic

Jizōden is the site of a ring-shaped group of blocks from the first half of the Upper Paleolithic, located on a terrace on the north side of the Iwami river in the southern part of the Akita plain. Based on dating of recovered carbonized materials, the site is known to be from about 35,000 years before the present.

Some 4,447 stone tools such as axes, knife-shaped stone blades, trapezoidal stone tools, and pebble tools were recovered from 14 concentrations distributed in the form of a ring. While this type of "ring-shaped block group" has been found at more than 100 sites nationwide, the current example is precious for its great number of recovered items.

Looking at the stone tool types in terms of their locations of recovery, knife-shaped and trapezoidal stone tools concentrate at the center of the ring-shaped block group, while stone axes and pebble tools are distributed around the periphery. Also, there were three places where burned rocks and bits of carbonized material concentrate, and the use of fire is thus inferred.

Traces left on stone tools from killing game

Among the knife-shaped stone blades and a portion of the trapezoidal stone tools that are thought to have been attatched to the end of a spear, traces of impact flakes produced when thrust into some object could be discerned, and these items had been discarded in concentrated fashion in the central portion of the ring-shaped block group. From analysis of trace marks left on the blades of a portion of the stone axes, it is inferred they were used for working hide. From these conditions it is believed that at the Jizōden site, a number of people butchered and consumed the game they had killed at the center of the ring-shaped block group, making the tools they needed at its perimeter.

Jizōden is a precious site for clarifying livelihood at the start of the Upper Paleolithic period. (Kanda Kazuhiko)

(principal artifacts, Jizōden Site)

Stone axes, knife-shaped stone blades, trapezoidal stone tools, etc. Approximately 35,000 years before the present. (1–4, stone axes) Length: 9.1–11.3 cm. (5–10, knife-shaped stone blades; 11–14, trapezoidal stone tools; 15, side scraper; 16, grooved stone tool) Length: 2.6–5.2 cm. The material of Item 3 is tremolite (a type of amphibole) gathered from the far distant western portion of Niigata prefecture. It was found to be very similar from a physical science perspective to a stone axe of the same period from the Nakamachi site on the perimeter of Lake Nojiri in Nagano prefecture, about 360 km away. Items 5–10 were retouched at the base and are regarded as having been attached to the ends of hunting gear such as spears, and also have traces of flaking from impact at their tips. Item 11 also has traces of impact flaking at the tip, and is thought to have been attached perhaps to the end of a spear. Item 14 has trace marks left from cutting wood, and is thought as possibly having been used for maintenance work on spear shafts.

Refitted material Approximately 35,000 years before the present. Length: 12 cm; width: 19 cm; thickness: 14 cm. Material for which it was possible to reconstruct the raw source stone with recovered stone tools. It can be seen that the source stone was brought into the site, where many stone tools were made by taking rather long flakes from it. The material is siliceous shale gathered from the Japan Sea side of the Tōhoku region. Nearly all of the flake tools at the Jizōden site are made from this material.

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