The year is 2011. It is a time of political upheaval in Japan. Shogunist rebels have overthrown the Japanese government and estabilished the oppressive Takega Shogunate. However, the Shogunate fails to impose it's will over much of Japan, and in the power vacuum many powerful clans take to the stage. Among these are a handful of elite ninja clans, interested only in warring with each other. All clans, small or powerful, have a shared ambition to unify Japan.
The above map shows the current situation in Japan as of 2011. It is currently divided in two by an isolated yet powerful Shogunate buffer zone in central Japan. The east is home to a handful of powerful clans and the Shogunate, all among the most likely to unify Japan. The main players here, the Takega Shogunate and the Fukoyari Clan, are in a state of near constant war, though the Shogunate armies are now beginning to fold under the might of the larger Fukoyari Clan. The Kyogre Clan, sacrosanct on their island fortress Sado, conduct guirella operations against factions on the mainland. The west is home to a large number of warring clans, all fighting over control of this region so they can oppose the clans in the east. Ninja clans have appeared here to fill the power vacuums, each warring with the other, yet all share a hatred towards the evil Eternal Moon Clan which controls the island of Awaji.
So you can identify the regions, I've given an external link to the regional map of Japan.