went to "Wait a minute, sensei. First, explain this Jutsu to me not just how to train it." Raiden asked when he saw Jiraiya was going to sit down and take a nap while he trained.
"Sigh, ok. listen here, this Jutsu is an A-Rank Jutsu made by the Fourth Hokage, It is a spinning ball of chakra formed and held in the palm of the user's hand. Right now only I and one more person can use it. Now watch closely."
Jiraiya formed a Rasengan in his hand and came closer to a big tree. He collided his Rasengan with the tree. His Rasengan went through half the tree while leaving rotation marks on the stump.
"This technique isn't limited by anything except the amount of chakra you put in." He said while forming a much bigger Rasengan and approaching another tree and colliding it with the tree.
The tree was utterly destroyed with a small crater left behind. Raiden who was observing with his Sharingan was astonished at how the Rasengan was performed.
"Thank you sensei. I'll start training it right now." Raiden thanked him and got to training with the water balloon.
Jiraiya laid down under a tree and observed. Raiden used his chakra to rotate the water in the ballon. With his excellent chakra control and his previous shape manipulation training, it was easy to rotate the water and make the balloon churn, but it didn't pop.
Raiden stopped rotating the water and started recalling what he saw with the Sharingan. The chakra in the Rasengan was in harmony with Jiraiya's own body chakra rotation.
'I figured it out! I was rotating it to the right while my chakra rotation is to the left.' He thought to himself before trying again.
He started by rotating the chakra to the left. The balloon started stretching on the sides but still didn't pop.
'hmm, maybe if I do this.' Raiden thought then started using the chakra to rotate the water in all kinds of directions. The balloon stretched in all kinds of ways and directions until it finally popped.
Jiraiya who was observing got up.
"It looks like your Sharingan really helped you with this step, but it won't be able to help you in the next one."
Jiraiya took out a rubber ball and used his chakra alone to pop it.
"Do you understand?"
"Yes, I have to increase the volume and density of my chakra output to pop the ball."
"Good, this probably will take a couple of days even with your control. I'll be leaving you to your training then." Jiraiya then got up and left to spend some time with Naruto.
Raiden was looked towards his leaving back then continued his training. Using the first exercise, he was able to rotate the chakra, but it wasn't strong enough to pop it and settled down once he stopped controlling actively.
He started training with increasing the amount and density of the chakra. This would take some time as he started trying to increase the volume and density of his chakra output.
He trained until it was afternoon, then went to meet up with Shisui and Itachi who he hadn't seen for almost 20 days.
After explaining his back to back missions and how his Sharingan had evolved, they started their usual training with Shisui helping them with Genjutsu for both of them and Kenjutsu for Raiden.
This routine went on for a couple of days until four days after he started to train in the second step, he was finally able to output enough chakra for the ball to pop.
He went to Jiraiya's house after not seeing him for four days as he trained. He knocked on the door and waited.
Jiraiya who opened the door was surprised.
"Oh, I thought it would take you at least a week. Having great chakra control, a massive chakra pool and the Sharingan really isn't fair to those from the same generation. They might start thinking it's them who are talentless." Jiraiya teased.
"Please don't tease me sensei. I have mastered the second step as you have said. What is the next step."
"Ok then let's go first, I don't want Naruto to see us and start asking for training again." He used a shadow clone to stay with Naruto and went with Raiden to the training grounds.
"Ok, the last step is the hardest one as you might have expected. You have to use the first two steps together. you have to contain the rotation of the first step and power of the second in a ball shape like this." And he made a Rasengan.
Raiden nodded before trying to do the same he released his chakra and started rotating it but it went out of control after a couple of spins.
"Here take this." He threw him a balloon. "You have to make a layer that is able to contain the chakra inside, use this ballon to get the image down."
"Ok, I'll be leaving then, even with your control this will take you a lot more time so we'll be taking missions from tomorrow and you can train on the road."
"Yes, sensei."
Raiden did his normal training routine for the rest of the day.
~~~
Two weeks and three C-ranks later, Raiden was in the training grounds holding a balloon that looked entirely normal. He let go of the balloon and started using his chakra on his other hand.
A blue ball of chakra started forming on his hand. It settled on the same size as the balloon and he went towards a tree and collided it with the tree. It had the same effect Jiraiya's had on the tree.
"Success!" He said forming a smile on his face before running towards Jiraiya's house. Jiraiya received him at the door.
Raiden made a Rasengan in front of Jiraiya "I've succeeded in learning the Rasengan, sensei!"
"Good job, and in only three weeks. looks like you really have an affinity for ninjutsu. With this, you'll start training in nature transformation!"