Board Thread:Theories and Speculation/@comment-3001903-20150829033326/@comment-8839944-20150926050036

Thekillman wrote: Seelentau wrote: Ya'll have to consider that Rasa learned the Magnet Release by himself as well, even though it's a Kekkei Genkai. I probably wouldn't take the whole "learned it/taught it" too literally. Given the influences of Tailed Beasts, it's possible that he somehow stole some of Shukaku's power. Alternatively, kekkei Genkai may sometimes manifest clearly (e.g. Ice Release for Zabuzas kid) and sometimes require conditions (e.g. Sharingan/ Himawari's Byakugan) to awaken. Maybe Rasa had Magnet Release all along but was unaware of it/unable to use it until he taught himself.

So all in all, people may be unaware of their Kekkei Genkai (wasn't kakashi unaware of his Mangekyou until Part II?) until they get to a certain point, so it may seem like they "taught" themselves while they actually just awakened it. I was under the impression that Kakashi knew about the Mangekyo and it's drawback when Itachi and Kisame first appeared in Konoha. You'd have to have the eye and have used it to know the drawback, right?

Further more, I was under the impression that he didn't use it because it strained too much on his Chakra. Thus in the timegap between the two parts he went and trained himself to use it. Making his body acclimatize better to the strain that the eye causes.