I was thrilled to find this book. It's historical fantasy (a favorite subgenre), it's based on Chinese history (awesome) and it focuses on friendships between women (even better). The book deals with the lives of eight diverse women from a variety of stations in imperial society, united by the secret sisterhood called "jin-shei." The main characters are likeable and it's easy to get involved in their lives (the beginning is downright magical). The plot is interesting if a bit unfocused. The book is mostly well-written, though in places it could have used a bit more editing. Fantasy elements are mostly low-key and fit well with the mysticism of the setting.
Unfortunately, Jin-Shei doesn't make it to five stars. Was it the gratuitously tragic ending, or the excess of main characters (eight in a book this size means some will get very little screen time)? More than anything, I think it was the concept of jin-shei itself. When women pledge jin-shei to one another, they become sisters, taking responsibility for each other's well-being... but not only that. If a jin-shei sister asks you for a favor in the name of jin-shei, you're not allowed to refuse. Period. Even if it literally kills you, and we see instances where it does.
Despite that, jin-shei is heavily romanticized by the author and treated casually by the characters. Alexander created such a diverse cast of characters that she seems to have trouble figuring out how they would all become best friends, so she skips that part and has them pledge jin-shei to people they barely know or even dislike (Tai and Nhia are the only pair who were close friends first). Who would offer an unbreakable oath of obedience in such circumstances (or ever, for that matter)? When things go sour, I would have liked to see some reexamination of the sisterhood, with characters wondering if it would be better to simply be friends, without the pledge. That never happens, and so while I enjoyed the story and characters, I was left with the impression that the author had dreamed up a cool concept but not fully thought it through.
I had a good time reading this book and would recommend it. However, I thought that its excellent sequel, The Embers of Heaven, was the better book.