Board Thread:Naruto Discussions/@comment-28568301-20180910173149/@comment-3279282-20180911114342

It wasn't excplicitely stated in the databook. However, YYR got an extra page with text that makes it appear to be more than simply combining Yin and Yang. Also, it got "Six Paths" as a subheader, which indicates that the two things are connected. In my headcanon, Six Paths chakra is simply YYR chakra.