Tama New Town Site No. 471-B is located in Inagi City, Tokyo, and was excavated in connection with the Tama New Town Development Project.
The excavation was triggered when 5 stone implements were discovered in the fuscous (dark brown) soil at the top of the Tokyo pumice layer in a site exploration on May 2nd, 1987. The surrounding stratum was Musashino loam, and the implements had distinct shapes compared to those excavated until then. This led to the conjecture that they could be more than 30,000 years old.
An emergency excavation of the site was conducted between May 28th and July 17th that year. The site is located on a branch hill extending southwards from the ridge of the Tama Hills at an elevation of 160m on the left bank of the Misawa River. The site itself, at an elevation of 127m, lies about 500m distant from the Misawa River and the elevation differential with the river bed is about 60m.
In the excavation survey, 4 stone implements were discovered in the fuscous (dark brown) soil at the top of the Tokyo pumice layer, and were given a date of 49,500 ±9,000 years by thermo-luminescence dating. Added to the 5 implements that triggered the excavation, this brought the total of implements discovered to 10. In addition to these, 3 more stone implements were discovered in the fuscous soil at the bottom of the Tokyo pumice layer.
The 10 stone implements found at the top of the Tokyo pumice layer are grouped together in this report as the "upper stratum tool group", and the 3 found at the bottom as the "lower stratum tool group".
The upper stratum tool group consists of 1 point, 1 wedge-shaped stone implement, 1 side scraper, 1 core, 1 hammerstone, and 5 flakes with small flake scars. All except the hammerstone are made of rhyolite, most probably originating from the northern Kanto region.
The lower stratum tool group consists of 1 spatula shaped tool, 1 flake with traces of working, and 1 flake with small flake scars. Although the flake with traces of working is made of agate, the other two are made of rhyolite, the same as in the upper stratum group.
Due to the composition of the tools and the flaking technique used in both groups, as well as the fact that the volcanic ash of the surrounding stratum is the Musashino loam layer, the tools have been dated to around the middle of the Meso-Palaeolithic period.