In the j korean list a jurchen sub general has to command the troops from a jurchen contingent. Can he command other troops as well?
Just the Jurchens.
Its covered by the section on internal allies at the front of each list book albeit maybe a bit indirectly.
ahhh, but its a sub not an ally
So it is. Think the same applies though as it doesn't say they can command other troops just that they must command "it" - it being the contingent.