So I was cheered to find what was looking to be another Ono treatise on the principles of governance turning into a murder mystery, of all the domestically comforting things. (Don't ask me why murder mysteries are domestic and comforting. They shouldn't be, by rights, but as a genre, they are.) And I was happy to read all the 'but all the doors are guarded and no one can enter that part of the palace except its three inhabitants and if it was one of them the guards at *their* chamber doors would have seen them leaving their quarters, but no, wait! there's a door between the king's quarters and that part of the palace OMG could it be surely not!! no no *wait*, there's a wall around the compound and one demon beast, flying low, could enter unobserved over it---' Only now we're back to theories of governance and sideways references to the original story, which you probably have to know to understand why perfect Sai-ou has made his kirin ill.
OTOH it's interesting to read all the etiquette stuff-- like, the Three Ministers who live in the section of the palace are the King's father, aunt, and younger brother. But no one may enter the ministers' palace. Even the king's cousin, also an important minister, is not allowed to visit his mother there. Nor are you told why this is so, which makes it much more convincing. Call this sort of thing etiquette or taboo and you've already classified it. Present it as The Way It Is and it reads as world-building.