Board Thread:Naruto Discussions/@comment-25645405-20141128183407/@comment-3279282-20141202051329

They are chakra natures, but they aren't elemental natures. They're not part of the elemental chart Yamato explained to Naruto and they work entirely different, because they're created during the process of creating chakra, not afterwards.

Yin chakra is normal chakra made of only spiritual energy. Combining it with elemental chakra would not create a new nature, because to create a new nature, one needs elemental chakra, as explained by Kakashi. I really don't see your problem here, sorry.