Wow, this was so good I'm not even sure where to start!  The worldbuilding is great --  there's a perfect blend of historical reality in all its grimness (poverty, illness, famine, misogyny) and Chinese cultural beliefs around the spiritual & supernatural made real -- so there are hungry ghosts, and the Mandate of Heaven is a visual event that can be seen by others.   It makes for a very different sort of fantasy than what I'm used to, and since I'm a huge fan of Chinese TV dramas, I found it very organic and of a piece with the rest of the worldbuilding.   The characters are interesitng and engaging, sympathetic without being simple, and the writing was incredibly moreish; I kept having to slow down to make sure I was really absorbing the book.   It was great, I'm really excited to see where the second one takes the story!