Bai, a light novel. It’s an ancient-style story with a slightly Japanese feel, a modest ensemble cast, and a focus on everyday life. The major developments come around Chapter 70. All the characters are adults, and there is a seven-year age gap. Please forgive the author’s limited writing skills.
I never expected Yi Qiongzhou to come to Japan, and I was even more surprised when she ended up staying at my house. It seems I’m not exactly thrilled to have her here... Well, she can stay, I guess. There are spare rooms, after all. But why does she hover around me every day, calling me “Big Sis”? Maybe it’s just a habit from all the time we spent playing together as kids... But why does she have to squeeze into my bed every night? Is the mattress uncomfortable? Hmm, sharing our everyday life together isn’t so bad. But what does she mean when she says she likes me? She must mean she admires me. After all, “like” means something different in Japan than it does back home. That has to be it.
Don’t dwell too much on the naming logic. I looked up plenty of information, but still couldn’t quite figure it out. (The blurb isn’t my strong suit. For guidance, please go to the main text.)