Amatsumikaboshi

Amatsumikaboshi (天津甕星; Literally meaning "August Star of Heaven"), is a powerful space-time ninjutsu granted to Yūmei Kokūzō accessible via his left Mangekyō Sharingan eye.

To use it, Yūmei flattens out his palm with all fingers lined adjacent to each other, leaving no gaps between them. The hand is then used like a sword and is slashed towards the intended target.

It has the potential to allow Yūmei's limb(s) to pass through any physical object (or person (physical or ethereal)) and destroy it (if only permanently or ephemerally), where it enables him to "delay his own existence" and as a result, slice through the third dimension.

Yūmei sends his hands (or a select number of fingers) to a separate dimension (not necessarily a pocket dimension in itself) and inserts them into the object(s) of which he seeks to destroy. During this time they remain intangible to touch in the physical dimension (although remain physically viewable); upon returning his hands to the physical dimension, the objects which were originally there, are 'pushed aside'.

Theoretically, this process is completed over one-hundred and twenty times per second, and like a pulling saw, destroys affected objects without any resistance. As this technique requires him to control this process at supersonic speeds, mastering it is extremely difficult. However, similar to how a saw can't cut unless it's pulled, this technique cannot cut if it is unable to pass through dimensions; this technique cannot affect those who do not reside in the physical dimension, such as those under the effects of Kamui's intangibility-inducing effect.

Through mastering Amatsumikaboshi, Yūmei has become capable of utilizing branch-techniques, otherwise known as Dimension Arts (次元芸術, Jigen Geijutsu).

Influence
In Japanese mythology, Amatsu-Mikaboshi (ja:天津甕星, "August Star of Heaven"), also called Ame-no-Kagaseo (ja:天香香背男, "Brilliant Male"), is a god of evil and of the stars, specifically the pole star. He is mentioned in passing in the Nihon Shoki as an opponent of Takemikazuchi-no-kami during the latter's conquest of the land of Izumo, and is sometimes identified with the figure of Takeminakata in the Kojiki.