...the fuuu? shadow tech related to genjutsu? for the love of goodness. Gimmie the link where it tells me that! If not, NO UPLUS
Shadow techniques are related to genjutsu type like techniques because are both activated through yin-release and manipulated with that type of chakra... i'm sure Itachi being the genjutsu expert that he is, he'd see the shadows being activated n controlled before shikamaru would have time to even move them/or make them do whatever. Itachi would have been able to sense it n feel that type of chakra activated a mile away.