I'm assuming people gave this a low rating as they didn't know that there is a TV show prior to this movie.
If anyone wants to jump into Japanese TV show than this is one the best show's i would recommend. And then watch this movie.
The only reason i gave this a 9 is due to the slight changes to the story as to what really happened during that Era in Japan.
If you check the TV show, it has a high rating so i assure you, this is worth watching.
Review by Ahmed Assadi from the Internet Movie Database.