This is mitigated by the fact that rivers are attractive places to live, so the odds that a target of conquest is on a navigable river are fairly high.
Gets pretty bleak if this isn't true, and if your foe doesn't have to stay put, much worse. The Chinese tried to scour the horse barbarians of the hinterlands a few times. Didn't go well.
Gets pretty bleak if this isn't true, and if your foe doesn't have to stay put, much worse. The Chinese tried to scour the horse barbarians of the hinterlands a few times. Didn't go well.