Since the survey of Lake Biwa Tsuzuraozaki Lake Bottom Site is extremely difficult for humans to conduct diving surveys due to the fact that the water depth extends to around 70 m and the influence of violent water currents, we have been using underwater robots manufactured by the research group since 2010. It has been held 2017 times over 16.

　According to the surveys conducted so far, the distribution of pottery from the Jomon period to the Kofun period, which is often found in the northeastern waters, is very small in the southern waters extending from the southern tip of Tsuzuraozaki toward Chikubu Island, from the 6th century to the 12th century. For the first time, we have confirmed that the distribution density of what can be regarded as a pottery of Sue pottery or Haji pottery around the century is high.However, the reason why the pottery was found from the bottom of the lake has not been clarified, and it is a mystery.

　In this survey, as in the past, at a depth of 71.5 meters at the southern end of Tsuzuraozaki, a pottery presumed to be a jar of Haji pottery made from the Asuka period to the Nara period was found in perfect form, and the image was acquired. Also successful.This video is academically valuable because it is the video at the deepest point that identifies the coordinates of the discovery point.The underwater robot owned by IDEA Consultants Co., Ltd. was used in cooperation with the certified NPO Biwako Trust IDEA Consultants Co., Ltd. and TBS Television.

　The pottery found is similar in age to the pottery found in this area, but due to its different form, it is unlikely that it was intentionally sunk at present.In the future, the research group plans to refine the images taken by the underwater robot at a close distance by using image processing technology, expand the survey water area and survey method, and analyze the excavated lake Seitetsu in detail. That is.