-People grew rice plants-
At the end of Growing rice plants disseminated through the country.It needed many workers to grow them, however it gave

The ruin of Itazuke (Fukuoka)
-The ruins of the Yayoi village and rice field-
The late
Jomon earthen wears and the early Yayoi ones were found at the ruin of Itazuke together. With some pieces of the late Jomon earthen wears called 'Yu-u-su-Doki,' carbonized rice seeds were found, too.The chalco-(bronze) swords and chalco-pikes made in Korea were also found there.

Kango-iseki and rice field (model)
Kango-iseki
The ruin of Itazuke was surrounded by a moat (6m wide, 3-3.5m in depth) to protect against the enemy. We call such ruins as
'Kango-iseki (the ruin surrounded by the moat).' The biggest 'Kango-iseki' in Japan is 'Yoshinogari' (40ha) in Saga .They say 'Yoshinogari' is not a village but a 'Kuni' (nation) during the Yayoi Period.
Yayoi-Doki from Itazuke-iseki
Why do we call these earthen wears 'Yayoi-Doki'?
Because they found these types of earthen wears first at Yayoi-cho, Hongo, Bunkyo-ku, Tokyo.
Have you heard the name of Itazuke?
Some Americans have heard the name of ' Itazuke' ...During the Korean War (1950-1953), many American planes flew over the Korea Strait from the Itazuke airport.We have no 'Itazuke airport' now.It is now called 'Fukuoka International Airport'.