I've known the story of the 47 Ronin since my teens. It's one of the most profound Japanese "factual myths", and has shaped and formed the nation. However, many Westerners don't understand why that is, or why it should be.
Video blogger and former astronaut Chris Hadfield has a very interesting YouTube channel, Rare Earth. In a series about Japan, he began by examining the legend of the 47 Ronin and trying to explain it to a Western audience. I think he did a pretty good job. Here it is.
I think that's one of the best explanations I've ever seen or heard of the myth that grew up around the 47 Ronin. The rest of the series about Japan is worth watching, too, and I return to Mr. Hadfield's YouTube channel regularly to see what new videos he's produced. Good stuff.