While hunting boar in Hyobu's Forest, an out of place stone was found near a small creek, a large lump of black granite quite like the stone composing the walls of Ryoko Owari. This turned out to be only part of a trail of such stones eventually leading to a tree grown into the creek exposing some of its roots. Stuck within a hollow inside was a small package wrapped in rough cloth containing 2 bu and a small scroll: "Continue watching NV. Recent disruptions should serve our needs. The coward has once again revealed himself, but that time is not yet right."
Kasuga Osamu has heard rumors about NV from the less reputable parts of the city. It comes in bits and pieces, but is eventually able to be pieced together into a place known as Necessary Village. Few believe it to actually exist, but it's spoken of as a sort of El Dorado for opium. A place where vast quantities of processed opium exists, guarded jealously by an entire army in a fortress city. Even those who share these small scraps do so only after looking around carefully and speaking in hushed whispers. It is the sort of place men would kill to possess or to keep secret. That is, before nervously laughing it off entirely. Obviously the delusional fantasies of drug addicts and nothing more.
It's reputed to be somewhere near Ryoko Owari, but reports always differ: hidden in some high mountain valley inaccessible to the outside, deep inside the darkest part of the Shinomen Forest, deep under the city in some forgotten cave, right outside the walls hidden in plain sight but protected by all manner of devious traps and illusions, etc.