It's been billed as a Mulan retelling, which I think is a huge stretch, as the only similarities are girl crossdressing/masquerading as a boy, a bit of learning to fight, East Asian setting and some similar lines at key junctures... However, it was an awesome read anyways. Things I appreciated:
-It's set in a very slightly altered version of ancient Japan (and as far as I can't tell, it's not quite #ownvoices), but the author doesn't get all weeaboo awkward about things. You know what I mean. The setting is well described and natural, with recognizably Japanese locations, objects and practices (seppuku! tea gardens! silk kimono! tabi!) but it doesn't have that breathless, adoring Western fanfiction feel, nor does it suffer from the stilted translations and stereotypical tropes of actual Japanese-produced light novels. Well-written world/Asian-set fantasy with a fluid blend of authentic historic and cultural detail and magic (and a slight bit of shifter-paranormal?)
-Mariko, the protagonist. She's smart, a problem-solver, not unrealistically brave, but determined and ready to step up when the moment comes. And we know this because she actually comes up with innovative, creative problem-solving solutions (in medieval STEM subjects no less!) Loved the way this was portrayed, that she found success and acceptance by leaning into who she was (not just as a woman, as a person). She's not perfect, unrealistically skilled/strong/genius etc., or even very nice/moral/heroic, but she does better the more she knows and accepts herself, and even if it's unrealistic that those around her accepted, approved and praised her for that, it's something I adore seeing on the page as a wish-fulfillment fantasy!
-solid storytelling with just enough machinations going on in the background. Some politics and stuff, but not overwhelming the story. Interesting treatment of the experiences of multiple women in the story world. I didn't totally buy the romance subplot, but it didn't really detract from the story for me (and given the Mulan comp, you had to know it was coming...). Without getting too spoilerific, the ending has what I now think of as a Sarah J. Maas signature twist; you're going to want to grab the sequel at your earliest convenience. I'm definitely tracking down Ahdieh's other books.