Board Thread:Theories and Speculation/@comment-26138683-20150322132758/@comment-4912646-20150322193500

I'd say the most confusing thing about Yin and Yang chakra is the fact that Minato somehow split Kurama's chakra into separate Yin and Yang halves. Yet there's no indication that its Yin half or Yang half have pure Yin/Yang chakra. Who knows if pure Yin/Yang is even possible, since even the chakra used in Tayuya's technique was said to be mostly spiritual energy, not entirely. According to databook 4's explanation, simply creating chakra is based in Yin-Yang Release so logically all chakra should contain some amount of both spiritual and physical energy, thus both Yin and Yang.

Also, not every technique falls under Yin or Yang, otherwise every character would have at least one of those in their databook nature chart, but a few have neither.