Who was the most powerful as a genin.

[LuckyMan]

Genins were established during the Tobirama era, along with all the ninja ranks and schools so before that there existed no ranks for Hashirama Madara so technically they never were genin.

 

[Scryed]

Didn't Obito make chunnin before the incident though?

 

[Sir Cool Blizzard]

Well....Current Naruto and Sasuke are the strongest genins of NV!! XD
But since u r asking at the age of 13...probably child Hashirama!!

 

[Nebula]

Madara and Hashirama don't have feats. Lol

 

[Gold Lightning]

Probably Kakashi and Itachi... oh and Gaara

 

[Red Beast of Konoha]

Itachi, Kakashi, Minato

 

[LeSauce]

Itachi, no doubt.

Guy was beating adult Uchiha, who are all elite btw, with little to no effort.

He had sharingan at age 8, that alone puts him above practocally everyone else else at that age.

The only ones that can compete are Hashirama and Madara.