Board Thread:Theories and Speculation/@comment-26388300-20150523085628/@comment-26379028-20150606154703

Mount Myoboku and Ryuchi cave are just the only known places to train for Senjutsu in, but not the only in the whole world. We have hashirama, I don't think that he summons either Frogs or Snakes. That leaves just the time problem, he could never go and train until he retires (And I think that he is still too young for this , even after 2nd timeskip).