Osaka Plain was originally a wetland,expanding in the lower reaches of the Yodo and Yamato rivers.During the early Yayoi period (ca 300 B.C. - ca 300 A.D.), with the commencement of the rice culture,the wetland was gradually converted into rice paddies.Since the 1960s the area has been rapidly urbanized,until only a few rice paddies remain.

• Geology of Osaka Plain
  
• City area