Board Thread:Theories and Speculation/@comment-1512913-20150719143657/@comment-5407586-20150719205047

Hashirama's Wood Release doesn't come from being an incarnation of Asura, though the vitality may have helped a little. Hashirama's strong not only because he's an incarnation of Asura (Naruto couldn't reach his level until getting Hagoromo's power, despite being Yang-Kurama's perfect jinchūriki and having senjutsu mastery), but also because he has a unique kekkei genkai.