[m-i-l]

This is all very good, but I don't think it is specific to Japan - I'd hazard a guess that most old world cultures have a history of eliminating food waste dating back to the days when existence was much more precarious thanks to war, pestilence and famine. Thinking of Scotland for example, there's haggis (heart, liver, lungs, and originally stomach), black pudding (blood), plus all those "recipes" for leftovers like stovies and rumbledethumps. And in Europe I've seen things on menus like pigs trotters, pigs ears and so on.