Dazai Osamu is a well-known writer in Japan, one of the most important writers of the 20th century, actually. But because of these facts, if you don't know nothing about the literature of that time, about the "buraiha" group and the story of Dazai and the other writers, you maybe will not enjoy this movie overall. Due to all of this, it's easy to understand because occidental viewers who would enjoy dorama, japanese cinema and even would know a lot of japanese culture in general, would not see this film as a good movie. But, in fact, it is. Oguri Shun is a perfect Dazai Osamu, the story they want to tell it's so real that is hilarious that thing like that could happen.

If you are interested in japanese literature, I totally recommend see this movie. And if your aren't, just do a research after see it. It's amazing.