Board Thread:Theories and Speculation/@comment-27924662-20161219053341/@comment-4271790-20161219053805

"Rinne Sharingan, from chapter 676"

- According to the stone tablet handed down in the Uchiha clan, when one who wields the power of Rinne approaches the moon, the eye which can reflect off the moon and grant the infinite dream will open.

Perhaps, because Hagoromo never attempted to get close to the moon.