Daimyo- The leader of a given Family.

Rikugunshokan - Commander of an entire Army.

Shireikan - Commander up five Legions (Around 25000 troops)

Taisa- Commander of one Legion (about 5000 troops)

Chui- Commander of 800-1000 troops

Gunso- Platoon leader (The wiki puts this at 50-200 troops, quite a variance!)

Nikutai- Squad Commander (5-10 troops)