Quote Originally Posted by XanBcoo
I disagree completely. This is how I see it:

To my knowledge, people are citing the fight with Haku as evidence for the "Sharingan can't copy bloodline limit attacks". This is because Haku, who's bloodline limit seems to be the ability to control ice (?), uses a technique utilizing only this. The attack is unique in that it doesn't follow the normal rules for a jutsu - making use of the bloodline technique. So, Kakashi is unable to see through it with the Sharingan.

Jyuuken, however, is its own style of fighting. One does not need the Byakugan to use it. The Byakugan only allows the user to see ~360 degrees, and the inner coils system. Jyuuken is otherwise completely unrelated to the Byakugan because it is merely a way of controlling and attacking with chakra. Only the Hyuuga use Jyuuken proficiently because they have the Byakugan to see the chakra system, but nothing else about the fighting style is unique to the Hyuuga.
Jyuuken NEEDS Byakugan to be used properly, as the Byakugan can see the Chakra system inside the body.

Jyuuken is not a Bloodline limit, but it is only usable by those of the Hyuuga clan.