Superb storyline. I watched the anime rather than read the book. Before watching it, I read the description of it, which didn't impress me.
But it had a good rating in the anime circles, and seeing 2 men kneeling on the floor with their kimonos, made me decide to watch it.
And all I can say is that the author is a genius in story telling.
Watch it for yourself, and decide, I'm sure I'm not wrong about my 5-star rating.
