1) Using 3D max open the "total war shogun 2\modding\raw_data\EmpireDesignData\campaign_maps\sho_japan\Shogun2.max".
2) Find a region without a town, such as the "jap_mino" region.
3) Clone a nearby town and move it to this region.
4) Right click on this town, select "Object Properties", and rename this town so that it belongs to this region. In this example "town:jap_south_shinano:region_specialty" is changed to "town:jap_mino:region_specialty".
If you moved the original town to the new location, rather than the cloned town, then you'll also need to rename the original town.
5) Hide all layers except the Settlements.cs2 [ports], Settlements.cs2 [settlements], Settlements.cs2 [towns], and Settlements.cs2 [trade nodes].
6) Hold down the <Ctrl> key and press the <A> key to select everything.
7) Press the 3DS button and in the pop-up menu select "Export", then select "Export selected". Export this file as the
settlements.CS2 in the campaign_map folder you're editing.