Board Thread:Naruto Discussions/@comment-25343176-20150612124722/@comment-26090730-20150613185357

NejiHema wrote:(...)And because the state the world was in, many people , must have went through tragedies , including the Uchiha. So many Uchiha must have awakened the Mangekyo before, and who knows , maybe some awakened the Rinnegan but again were forgot because of being warmongers. Mmm are we forgeting this again ? Just in case you don´t remember :

Asura´s chakra + Indra´s chakra + Sharingan = rinnegan

I question to you, how would an Uchiha know who is the reincarnation of either of the Sage´s sons in order to get their chakras and therefore get the Rinnegan ?