I don’t think this was in the book, so taking bets now on if Song Yunhui wrote anything on that paper airplane.
I didn’t think it would be possible to cast people more like a character than the book portrayals, but here we are with Like a Flowing River 大江大河. Wang Kai, Zhou Fang, Yang Shuo and Dong Zijuan actually have the perfect qualities to fill out what I think are inconsistencies in the characters in the books (Tong Yao’s character is already perfect).
My only concern is Jin Chen. Imo she’s the actress who has the most on-screen chemistry with Wang Kai, but her character was so unrealistically perfect and unlikeable that she would need a major overhaul to work. I will likely be rooting for Zhou Fang’s character.