Morimoto iseki is the trace of a paddy field and waterway of the Yayoi Period. The City found them while building the civic dai san Koyo primary school in 1960. Morimoto iseki is a typical Yayoi Period paddy field now as famous as Toro iseki in Shizuoka Prefecture. Many kinds of farming artifacts such as earthenware, stone implements, hoes and stone knives were excavated. One very rare earthenware item with a human face was also excavated here.