If you could learn one jutsu...

[Meowazziel]

Seriously people. Do you even read past the title?
He said NO DOJUTSU AND NO KEKKEI GENKAI, yet people list these things as answer from the very start...

Anyway, I would like to learn kage bunshin no jutsu.
Reason:
I could do more stuff at once.

 

[Enigmatic]

Lightning Release

 

[Shodai Hokage]

Yin seal/release or medical ninjutsu.