Well my anime culture in stuck in the middle of the 90’s , i don’t remmember seeing any shamisen in Cinty Hunter or Ranma
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Nitaboh is a great idea for promoting the shamisen , it’s modern style anime and the animation with the shamisen and the sync with sound is amazing , if i need to say something bad about this movie , they totaly failed at drawing the Tenjin but that’s ok
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Anyway , Amanda your idea is awesome, i had the same few month ago but then thought “well there will be a majority of naruto and one piece fan , they even give a damn about traditional culture” but i’m sure i am wrong and people will love it , a good thing would be to show some bachi as well maybe ? 
I’m maybe too much of a fanboy but , another good way is to tell about the game Muramasa : the demon blade , the ost contains a lot of shamisen and traditional music in general mixed with some badass metal . Sometimes you can see shamisen in the buildings in chinese shadows , not much but the game is based on Japanese myths … i’m acting fanboys , just check the ost 