While I examined the thing of the chain, I noticed that one had to take the anchor used together as one function away in the theme. Then, I tried to collect it.
It was not modest life by picking and the hunting, but a big village was established, and it was proved that it was cultural advanced life in the recent research as for the life of the people of the Jomon period which I learned in the school days.
It seems that they were doing dynamic activities of crossing the Pacific Ocean in the time.The big log ship which exceeds 7m is excavated in the Torihama shell mound of Fukui Prefecture.
The Maori group who was the aborigines of New Zealand rode on a ship like a photograph and came from the island of Polynesia to there． They dug a hole in the stone, and then tied a rope to it and they were being handled as an anchor. 　
（Auckland museum）
By the way,The anchor of such a stone was being used for the whole area of the limb Pacific Ocean including Japan and each place in Europe.

A right figure was seen in Okinawa prefectural museum.