To carry on my theme of noticing useless crap.
When Naruto and Jiraya were talking about the exam their jounin teacher gave them before becoming genin (the thing where they had to get the bells) there is something weird.
Naruto mentions that he was the one who was tied up to the tree.
Jiraya then remembers that he too was tied up to the tree. However, in the flashbackm you see Tsunade holding one of the bells up in front of him.
We all remember from Kakashi's test that the point of the exam is teamwork and that you are not supposed to be able to get the bells individually.
So, either Tsunade and Oro were strong enough at that age to get a bell from the 3rd.
Or, the exam was slightly different back then, and teamwork wasnt the point, which is unlikely as it is made clear that the same test was handed down from the 3rd to Jiraya, to the 4th, and then to Kakashi.
I guess it doesnt really matter though.