In the small islands southeast of the main islands of Japan, life were characteristic of those during the Paleolithic Period in the first half of this period, but the shell mound period started around 60,000 years ago and continued until around the end of the Heian period.
南西諸島においてこの時期の前半は旧石器時代が継続していたが、約6千年前以降に貝塚時代に移行し、およそ平安時代末期まで続いた。