Benzaiten (弁才天, lit meaning, She who controls all flow) is a technique which is seemingly derived from the very powerful Tsukuyomi, invented by Tsuna Uchiha.
Banzaiten unlike Tsukuyomi doesn't require eye contact, but captures those within the vicinity. This technique allows Tsuna to open the route of his target(s) mind and manipulate their memory. Tsuna is capable of erasing memory, editing memory, or even "input" memories. By editing, Tsuna can make it appear as if something happened back then, when it really didn't. When inputting new memories, Tsuna usually implements things into his opponents life to make them believe it. In a battle, he once added a memory that he was there during the dying moment of the opponents family. Lastly, by erasing memories, he can completely remove them without a doubt, or fluke.
Benzaiten (弁才天 or 弁財天) Also known as Benten, she is the goddess of everything that flows: words (and knowledge, by extension), speech, eloquence, and music. Said to be the third daughter of the dragon-king of Munetsuchi, over the course of years she has gone from being a protective deity of Japan to one who bestows good fortune upon the state and its people.
Tsuna has stated he's altered the memories of the Water Daimyō, but hasn't stated whether he used this technique or not.