All four of these episodes are really good, I learned a lot. There is also a 5th one about the boxer rebellion specifically with the same guest

I was just listening to this today! It's really good!

They'll tell you at the beginning to go back and listen to the introductory episode, and if you're someone like me that doesn't have a strong background in Chinese history, I agree that it's really worth doing, since they give kind of a high-level overview of the whole thing, and then this series really dives in deep.