Board Thread:Boruto: Naruto the Movie/@comment-26010916-20150722020206/@comment-1732320-20150722211513

What series are you following Elveonora? Databook said it was one of their [many] kekkei genkai and Kakashi explained this in the series. Shinobi can generally only expel chakra from their hands and feet. They Hyūga can do it from eyery tenketsu in the body.

Also the Byakugan is not needed for the use of the Gentle Fist. You don't need to be able to see the tenketsu to damage someone's chakra network. Recall that in the Konoha 11's chūnin exam, Hinata was shocked that Neji could even see the tenketsu. It's an ability gained with the progression of their dōjutsu.