Board Thread:Naruto Discussions/@comment-24373005-20141013001519/@comment-1512913-20141013094845

Besides Six Paths Yin and Yang Powers, Hagoromo also gave Naruto and Sasuke his chakra. They lost the tattoos, but not Hagoromo's chakra.

As Seel said, Sasuke attributed his eye technique to Hagoromo's chakra and Naruto's Truth Seeking Balls were attributed to Hagoromo's chakra.

While possible that Sasuke's Rinnegan may be because of Hashirama's chakra/cells, I find it more likely that it's because of Hagoromo's chakra rather than just a single technique of his Rinnegan being because of his chakra.