Why Chushingura?
There are multiple reasons to use this film: it's a story known to just about all Japanese and so presumably is (after 300 years) highly relevant, it encodes ideas widely recognized as essential to Japaneseness (Buruma fingers on and giri) and so gives us another shot at thinking about the problems of semantic mapping and translation across cultural boundaries that anthropology wrestles with, it offers plenty of ambit for inquiring why people act as they do, and it raises issues of honor that contrast --or at least map interestingly with-- the vaunted essentials of W&L's ethos.
A couple of years ago I put together a collection of links to materials on Chushingura ...a few links may not work, but most do.
Turns out it was Miyazaki who made Wan Wan Chushingura ("Miyazaki's first job as an animator was in-betweening on Wan Wan Chushingura (Watchdog Bow Wow) in 1963..."), mentioned by Buruma.