. So, yes, I do claim otherwise. Adding tengu and other folklore inclusions in the story is an invention of the movie producers, and not in any previously written version of the story.
The Japanese have a word for retellings of the 47 Ronin story: Chūshingura.
You know the Power Rangers? The action sequences for Power Rangers are taken from the Japanese "Super Sentai" franchise.
Juken Sentai Gekiranger is the 31st entry of that franchise. It includes an episode that features its own spin on the Chūshingura, with the main heroes being sent back in time and Kira having been possessed by a Rin Jyu Ken user, whom they defeat before the Akō incident starts, and thus not interfering with it.
If the Power Rangers can get into the story, it is not nearly so sacrosanct in that culture as you make it out to be.
Regarding the point of Shogun as a TV series (I did clarify that it was a television show and not a movie in my original post). Really what does a different medium have to do with anything?
What does the medium have to do with anything??
Well, let me take the example I already gave - the story of the 47 Ronin has been made into an opera. To do so successfully, they had to add music and lyrics, did they not? The historical Ronin didn't actually sing quite so much did they? And neither did the puppets in the original play, nor the kabuki actors in those versions, correct? So, in general, we accept that some adjustments must be made to fit a new medium.
Each medium comes with its own set of tropes, restrictions, additional features, and audience expectations. Making a successful (and by that I mean widely viewed and critically acclaimed) presentation in any particular medium calls for manipulating the story into the medium.
In the end, I don't believe adding fantastical elements to any movie automatically increases it's revenues.
Who said automatically? I didn't. Fantastic elements are not sufficient to reach the goal, but in some sense it may be required for the modern American movie audience.
Take a look at the top grossing movies of 2013:
http://www.boxofficemojo.com/yearly/chart/?yr=2013
In the Top 10 are *no* straight up drama films. None. The closest to it is "Fast And Furious 6", which has fantastic levels of action.
We don't see a historical drama until we get down to #24, with "Lee Daniels' The Butler", with a gross of $116 million. I don't think we see a single other historical drama in the top 50. If historical dramas sold well to the US film market, the one entry would have done better, would it not? Would we not have seen more such entries? The Butler has relevance to US history, and speaks to a large chunk of the US audience in a way that the 47 Ronin don't. The 47 Ronin aren't part of US history or culture. The vast bulk of the audience just doesn't care about them a whit. If you presented them, as-is, the US audience just wouldn't care. Historical dramas are a very hard sell to begin with - an irrelevant one is basically asking to fail.
It is easy to claim that something is unnecessary when you don't have to make a profit at doing it.