This chapter broke one and maybe a half of Knox's commandments.
- Followed? It depends on how you define "the early part of the story;" The crow was mentioned and showed up before the reveal, at least. It was only in a flashback, though.
- Followed. There were no supernatural or preternatural forces at work. (Except maybe the crow talking, but that didn't have anything to do with the crime or solving the case.)
- Followed. There were exactly zero secret passages.
- Followed. There were no strange poisons or complicated contraptions. Kusuri didn't even show up this chapter!
- Followed. There were no racist depictions of Chinese people.
- Followed. The case was solved with sniffing— There were no accidents or intuition involved.
- Followed. Hasuha did not commit the crime.
- Broken. Hasuha did not mention that she smelled the crow's scent at the scene of the crime.
- Followed in the sense that Hasuha did not have an assistant at all.
- Followed. There were no twins. Kusuri and Yaku didn't appear.
I was expecting more from Hasuha, and I hope she'll learn from this mistake and do better next time.
And it broke Van Dine's 1st, (Same reasoning as K8) 5th, (It's specifically mentioned that this was not a deduction) 7th, (No corpse) 10th, (I didn't particularly care about the crow.) 15th, (Bit of a personal opinion, I guess, but I don't think you could solve it until the crow was mentioned, which means it
was not "staring [the reader] in the face") and 16th (This characterized Hasuha.) rules, but they're are a bit silly and overly strict, so who cares.