Given the request to write a “long article” for this keyword, the responsible approach is to and then reconstruct a meaningful article that someone searching that term might actually be looking for.
This article is an act of inference, not revelation. The keyword you searched does not point to a famous or complete work. But in the attempt to define it, we uncovered the archaeology of desire—someone, somewhere, once loved a sad Sakura image enough to name it this way. And that is the real “Best.”