Sunadokei

Sunadokei (砂時計, Hour Glass) is a powerful and versatile genjutsu devised by Heiwa Uchiha, which is used as an alternative to visual genjutsu of his clan. Considered one of the most incredibly difficult techniques to learn, the versatility granted by it is worth it, as one becomes an absolute powerhouse in the use of genjutsu.

Usage
The technique is quite versatile, in a way that it can be applied in any way by the user. Visually, through hearing, touch, smell or even the tastebuds. However, it still requires a handseal to be formed. Once the handseal is formed, the user may look into the target's eyes, or utter words or even form a foul stench, all of which are used as mediums to cast the genjutsu. Once in the genjutsu, the user is able to alter the target's perception of time. Unlike the famed Tsukuyomi, it alters it in a vice-versa form. A single second in the genjutsu can be almost ten seconds in real life, or perhaps even more, depending on the user's mastery. This makes the technique perfectly useful for delaying it's victims. The user is also able to fabricate anything in the illusion, and can torture or even incapacitate the victims with minimal resistance. The technique is incapable of being released through conventional methods, such as stopping one's chakra flow, and as such, it is renowned as a genjutsu of high calibre, within the ranks of the Tsukuyomi itself.