genjutsu is also like that. itachi casts it with left while sasuke does it right.
they are the opposite of each other, it hasn't been explained why.
but I think it's well known![]()
Sasuke is left handed, and Itachi is right handed, that's probably why.
(proof: see chapter 393 where Itachi reaches with right hand to Sasuke's forehead. Any chapter showing Naruto and Sasuke doing their Rasengan/Chidori clashes always has Sasuke using left hand while Naruto uses his right)/