Hi. Pete, here. I’m working on a complete rewrite of theses Yanagisawa pages and have been since June 2014. You can see what I’ve got so far HERE. I’ve also posted some updates to the Yanagisawa serial number charts. I also have a Forum topic where I talk about my current progress.
Note that the pictures in this article, here, for the 6, 500, 800, and 880 Series horns might be incorrectly categorized. I’m working on it.