Although pots had been invented by hunter-fisherfolk of the earlier Paleolithic people, they were not terribly useful to the nomadic people. It was only when storage pits began to be used that people began to settle down for longer periods of time in their pit house hamlets or villages. Once food could be stored in pits, people didn’t need to move around following their moving live sources of food anymore. Experts believe there is a strong connection between the use of the storage pit and the semi-sedentary lifestyle of the Jomon people.
Model of a Jomon storage pit (Niigata Prefectural Museum)
The storage pit from Jomon times comes from the the Higashi-Kurotsuchida site in Kagoshima prefecture radiocarbon dated to 11,300 years ago (to the Incipient Jomon period). A storage pit with large quantities of konara acorns (Quercus serrata) inside was discovered. These acorns had to be first soaked in water, then boiled to remove the bitter tannic acid before they could be eaten, which meant that the Jomon people had already by then developed a sophisticated method for removing the tannic acid.
The storage pit is the most common characteristic that is noted of Jomon settlements everywhere, so researchers believe that nut storage played a most important role in Jomon survival and in their food-collecting strategy. Click here to see what the storage pit looked like and how it was used.
A wide variety of nuts were stored during Jomon period (Kawasaki City Museum)
In Western Japan, wet storage pits are common — in which layers of leaves, wood fragments and clay are used to line the pits, or mats and baskets may be used to store the nuts.
In eastern Japan however, dry storage pits, often flask-shaped pits are found. Food remains have not been recovered from these pits, so scholars assume that food was first placed in containers such as pots or baskets before being stored in the pits. They think the pits were also used to store acorns and other nuts.
Why were the pits of western Japan wet? It is thought that the wet pits would keep out insects or that the nuts preserved in these wet pits would be prevented from germinating for a long time, tens of years. This ensured a food supply in case of famine.
Apart from underground storage pits, some settlements also had raised buildings that were probably storage houses or warehouses. Hundreds of these raised storage houses were found at the site of Sannai Maruyama village. In addition, large building with huge columns is an outstanding architectural feature of the Sannai-Maruyama ruins and may have been a huge raised warehouse or large trading hall for servicing the Sannai-Maruyama village as a trade center.
Raised warehouse beside a pitdwelling on the Omusaro Plateau near Monbetsu, Hokkaido
Heritage of Japan 