If I remember right there are two ranks. Daimyos who are heads of clans, and then another title (can't remember the name) who are their vassals.
I would imagine it being..
Shogun/Emperor (King/Pope)
|
Daimyo (Dukes)
|
Kokujin (Counts)
|
Samurai (Barons)
The emperor would probably be somewhat like the Pope position in CK2, I would imagine.