I just watched the latest filler and in the end Konohamaru blowed away like 5 sumo wrestlers and made a huge crater just from one rasengan. When he made his clone it made a small rasengan but on the way to his enemies he switched its size.
By this i belive Konohamaru is better on doing the rasengan than Naruto , and he might be able to do it without a clone in the future.
By this i belive Konohamaru is better on doing the rasengan than Naruto , and he might be able to do it without a clone in the future.