User blog comment:SakuraKarakura/Ch 396: Explanations, Proofs, and Theories/@comment-1747976-20100323150544

Again, I believe that he read the reiatsu in the 'palm' of his hand. Two frames are shown with him observing it. He doesn't mention all of that until after asking about that being his reiatsu, then saying, "amazing..." Then speaking about his battles. Another manipulation given the opportunity.