Board Thread:Episode Discussions/@comment-25319479-20180531110046/@comment-30323490-20180602140844

She probably only has 1 tomoe because unlike the others, she didn`t really experience emotions to a high enough level for 2 tomoes when she awakened. Sasuke and Itachi saw their beloved die. With Obito wasa matter of death as well when he awakened it. Sarada awakened it because he got overly excited about seeing Sasuke, which wasn`t an emotion as high like the others experienced.