Back in 1990, I bought a handmade solid-silver Yamaha CY headjoint at Best Music in Oakland. I bought this particular CY head (a demo that they had behind the counter for $370), because I was so impressed by the way it played in comparison to all the other headjoints I had. In fact, so intrigued was I by this head that I ended up calling Yamaha in Michigan to find out more about it.
During my conversation with the Yamaha rep (Tom Wheeler?), I was told that Yamaha had seven old men in Japan that handmade their pro headjoints (starting in 1992 however, Yamaha began machine manufacturing the CY heads except for those on their most expensive pro model flutes). When I inquired as to how they came up with the CY cut for their 581 model pro flute, I was told that when Yamaha was doing their R&D, they actually had sixteen headjoint designs in a box. This box had been flown all over the world to professional flutists in major symphonies. The flutists were asked to vote for the cut they liked the best and the overwhelming favorite was the CY, and so Yamaha went with that. Apparently, such R&D is typical of the way the Japanese do business - smart!