The words yin&yang has been used in TWO DIFFERENT CONTEXTS in the series.
- When yin&yang are used to describe the type of technique, kishi is referring to whether its a dark(yin) or a light(yang) chakra manipulation. Where dark(yin) chakra manipulations have more spiritual energy than physical energy and light(yang) chakra manipulation have more physical energy than spiritual energy.
- The second case is when these terms are used with spiritual energy(yang) and physical energy(yin), the components that form chakra.
From the manga the definition of yin&yang are revealed by Madara regarding So6P's Izanagi jutsu which uses both yin and yang chakra manipulation.
- By administering imagination and spiritual energy which forms the basis of "YIN" power. He would create shape and form (Yin = The physical) from nothingness.
- By administering vitality and the physical energy which forms basis of "YANG" power. He would breathe life (Yang = The Spiritual) into that form.
The concept(Chinese in orgin) of how yin-yang works is based on a simple rule that one can't exist without the other, you may have heard of the famous phrase "For every Yin there's a Yang". Therefore dark(yin) and light(yang) chakra manipulations both count as ONE chakra manipulation as dark(yin) and light(yang) chakra manipulations BOTH need physical energy AND spiritual energy.
Here are some examples of yin&yang use in the series;
- One of the things So6P used Izanagi for is to create the tailed beasts, they have physical form as seen from the eight tails when his horn got chopped and the nine tails could be restrained(first hokage with wood, kushina with special chakra chains). They also have a conscience, the eight tails has a benevolent demeanor while the nine tails has a sadistic and violent demeanor all of which were created from the Juubi's chakra.
- The fight between shikamaru vs Tayuya(sound 4 ninja), there was a dark(yin) technique used. It was explained because the technique's chakra has more spiritual energy the chakra tries to feed on a body(physical energy) it comes into contact with to balance itself.
- And finally Jiraiya said Minato sealed the spiritual energy(yang) part of the fox's chakra within Naruto and the physical energy(yin) within the death god.
NOTE:The Uchiha and the Senju have inherited the dark(yin) and light(yang) bloodline limits of the So6P but that doesn't meant those two clans are the only ones that can have an affinity torwards dark(yin)&light(yang) chakra manipulation or even use dark(yin)&light(yang) chakra manipulation. Having an affinity allows you to use strong jutsu in that chakra manipulation's field. All shinobi can use jutsu from all chakra manipulations but are weaker if they don't have an affinity towards that manipulation. Kakashi's analysis during the Kakuzu fight explains this well, based from all the shinobi we have seen so far you can have up to 3 manipulations. Nagato/So6P are the exception, as the rinnegan gives affinities to ALL 6 chakra manipulations.
Now that we have a sound idea of how yin-yang works, lets apply this to jutsu we have yet to identify their chakra elements. The next three jutsu are special cases.