The field consists of lots of hexagonal tiles. And, each hexagonal tile is called as 'Land'.
Each Land has its own level. The higher the Land Lv is, the more resources you can obtain form the land.
Each land has a different type of resources. Obtainable resource can be checked from land sign.
[Occupying Land]
Lands with no building, resource site, city and monster are called vacant lands.
Vacant lands near castle can be occupied by battle.
When you occupy a land, resource which is produced from the land is obtained automatically.
You can increase the maximum number of occupied lands by upgrading headquarters.