Her diary is the Yukiteru Diary, which tells her everything about Yukiteru in intervals of ten minutes. While this means that her diary is basically useless by itself, if combined with Yukiteru's Random Diary that predicts Yukiteru's surroundings, it can cover Yuno's weakness and protect Yukiteru, making the two a fearsome duo. Even while the diary does not help her much by itself, Yuno can more than enough make for it with her cunning intelligence, which has saved both Yukiteru and herself several times. She makes up most of the plans the pair uses to save themselves from the attacks of the other participants. Yuno is also very proficient at quickly determining the weaknesses of certain diary users, like Yomotsu Hirasaka and his blindness, or discovering that Tsubaki Kasugano's followers were pretending to be dead waiting to ambush them.