Daiju (Die-joo)

This isolated region was once secluded by mountains but saw it's landscape crumble with the Great Deluge. The mountains got destroyed and the previously known Endless Sea (now named Eastern Ocean) surrounded the remaining places.
  This shifted the landscape. Now, rice fields are spread throughout the land, as water became more abundant.
  While the southern part of the region has a tropical climate, the northern region has a colder environment.
  Close to the Chientzu and Radhaputni regions, the Great Deluge also saw the Unknown lands to the East become closer, with Daiju being the nearest region to it.

Maps