Board Thread:Naruto Discussions/@comment-1018594-20160409062530/@comment-25122992-20160416191028

Emm, the first hole in his heart was a genjutsu, Obito used it to metaphorically show Kakashi the emptyness of his heart. The actual wound was inflicted by Kakshi in the final clash of their battle, when they stabbed each other with Raikiri/kokushin.