this is from Narutowikia
The Yata Mirror was an ethereal shield wielded by the left arm of Itachi's Susanoo. It is said to be endowed
with all nature transformations and as such changes its own characteristics to completely negate any opposition, whether it be spiritual, or physical.
totsuka
It is sheathed in a sake jar; the blade is unlike any other ones. Instead of a physical, metallic form, the blade is actually the liquid inside the gourd that is released and shaped, rather than a conventional sword. It is an ethereal weapon with an enchanted blade capable of sealing anything it pierces. Those who are stabbed by the sword are drawn into the jar and trapped in a genjutsu-like "world of drunken dreams" for all eternity; by extension, Itachi also managed to remove the Cursed Seal of Heaven from Sasuke by stabbing and removing Orochimaru from Sasuke's body. It can also cut through objects like a normal blade, thereby giving the wielder great versatility in his attacks. Being a variant of the Sword of Kusanagi, this sword can cut through almost anything, as seen when Itachi easily decapitated seven of Orochimaru's eight-headed snakes. Orochimaru sought the sword for all his life and Zetsu commented that he could never find it.[2]
basically meaning that i soloed your thread
