I don't think that's true either. I think it was just the first such to get translated to English. I think it's popular because the premise is interesting. The Dark Forest is just part of the vocabulary now, and that's not an accident, it's genuinely worth thinking about and, if not technically new, at least newly popularized.
On a "technicality" front, I'm sure you could find something if you dug through the archives, but really there was no hard modern scifi in China that was heavily published and got any traction until TBP. The party even discouraged fantasy media. I lived there and hung out with nerds, and they were ecstatic when the book came out.
