During the Yayoi period of Japanese history (3 c B.C. to 3 c A.D.) both the cultivation of red-grained rice and the shift from a nomadic lifestyle to permanent settlements, both very important cultural developments, occurred.
The largest ruin among all the Yayoi ruins excavated in Japan, Yoshinogari spreads throughout the Kanzaki area of Saga Prefecture (Kanzaki town, Mitagawa town and Higashisefuri village). The Yoshinogari ruins, as the center of the "nation state", have proved invaluable as a source of understanding of the approximately 600 years covering the Yayoi period.
The country of "Yamatai", modern day Japan, was first mentioned in the Chinese chronicles "Gishi Wajinden". Corresponding in both period and location, the Yoshinogari ruins are believed to be this ancient country making it a national site of special historic importance.
Furthermore, relics found at the site, including copper/bronze knives and decorative glass beads, show the extremely high academic value of Yoshinogari.