Flying thunder god plot hole

[the last shinobi]

Well i have an idea, the third Hokage was call 'the professor" for knowing all the jutsu in the village and he was alive when the 2nd was alive he could have learned it then and taught it to minato. Just because we don't see him use doesn't mean he doesn't use it.

 

[foxyladyland]

Sarutobi , Hiruzen was Tobirama's student so He knew about Tobirama's and Hashirama's jutsu...
as Hokage, since Minato had FTG before he was Hokage, Hiruzen most likely saw the potential in Minato
just as Jiraiya did as a genius, so decided to give him the benefits of it ..
Or Minato is really related to Tobirama and just discovered on his own...or by studing Tobirama...
I was waiting on someone to ask this question.
also it could have been a scroll ....
and it was given or taught to him just like summoning toads for Naruto, and Minato...
and other things in narutomanga, it was passed down gen to hopefully next gen after that.