Well, I was think about the 3 known dōjutsu from the manga (the anime has one more but that one doesn't matter in the storyxd) and you have the Sharingan the Byakugan and the Rinnegan. But know I was asking my self, you have the Sharingan and Byakugan which are dōjutsu of a clan and the Rinnegan as a 'special' dōjutsu, but why are the 2 dōjutsu clans only part of Konohagakure? It's a bit strange that 2 out of three visual jutsu's belong to one village, why doesn't Kumogakure or Iwagakure have a visual jutsu?