Board Thread:General Discussion/@comment-1875854-20150221232630/@comment-2253300-20150223160154

PG adding Yin or Yang is literally just increasing the amount of spiritual or physical energy that's in the Chakra you're using. It's a fairly basic skill. It would be childs play for a ninja with enough training to increase the amount of Yin or Yang in his/her Elemental Jutsu. So if adding Yin or Yang resulted in an Advanced Chakra Nature then literally anyone with the training could do it, no KG needed.