Jūrojin

Jurōjin (God of Wisdom and Longevity) is an extremely powerful genjutsu that is unique to the Korōshiya Clan's special dōjutsu, the Takara Tentougan. In order to be activated, the user has to make eye contact with the target. This allows the them to enter a genjutsu in which time is frozen outside the genjutsu. This allows the user to search around the target' mind, and find any information, ranging from strategies to fears, to things the the target themselves, don't remember. The user can even learn the how to use certain jutsu that they didn't know how to use before. In fact, they can learn absolutely everything about the target, and remember it. Outside of the genjutsu, it seems that upon activation, and completion of the jutsu, that no time has passed. This is an extremely powerful genjutsu that allows the user to learn weaknesses of all jutsu, even taijutsu.