Board Thread:Theories and Speculation/@comment-32742265-20180119154238/@comment-6769189-20180209222554

Yet Sasuke did it first try. So Gai wasnt referring to the Sharingans inability to copy it he was referring to the grueling physical conditioning needed to pull it off. He explained this within those same pages. Normally it would take immense practice and training. Since Sasuke had the conditioning already he didnt need to practice because of the Sharingans copy abilities.