Jiraiya wanted to test Naruto Uzumaki's strength.
This wasn't a sudden whim; he had many reasons. The most important was to observe the state of the Nine-Tails' jinchuriki seal, especially after Team 7 had to rely on the Nine-Tails' power to escape the bandits' hideout. It was highly likely they would encounter more enemies on their journey. If Naruto used the Nine-Tails' chakra during a battle but couldn't control its power, he could become a bigger threat than the enemy.
Beyond that, Jiraiya also wanted to see Naruto's own fighting habits. After all, Naruto was the next-generation legacy of his student, Minato Namikaze.
Time was short, and there was no faster way to test him than through direct combat.
To avoid attracting the attention of other ninjas, they found a hidden valley near the Village Hidden in Hot Water to use as their training ground.
Jiraiya looked at Naruto, his face more serious than ever before. "In this fight, you can use any of your powers, including the Nine-Tails inside you." He even hoped Naruto would use the Nine-Tails' power, as it would give him more information through direct experience.
Naruto, however, just shook his head. "After the last battle, the Nine-Tails is too tired. It can't provide me with chakra anymore..."
Jiraiya was speechless.
You've got to be kidding me. How could the Nine-Tails not be able to provide chakra? It's the strongest Tailed Beast in the world! How could it be tired from one small battle? Has this kid been tricked by the Nine-Tails?!
Jiraiya's original plan was to push Naruto into a corner, forcing him to draw on the Nine-Tails' chakra. Now, the situation felt a bit strange. Don't all Tailed Beasts desperately try to release their chakra to influence their jinchuriki's will and transform them into the personality they desire?
The whole process of a jinchuriki's training is to desperately maintain their own will and not be corrupted by the Tailed Beast when it releases its power.
The Nine-Tails... why was it acting so laid-back? It was so stingy it didn't even want to provide chakra.
If the Nine-Tails knew what Jiraiya was thinking, it would definitely stand up and tell him that a Tailed Beast provides chakra for a purpose. However, Naruto could easily make the beast's chakra his own, and the fox saw no hope of ever changing him. So why should it continue to provide chakra?
It was like a tragic, unrequited love story. If Jiraiya devoted himself to a woman who was a bottomless pit for his money but never even let him hold her hand, would he keep trying?
"Forget it, let's just give it a try first..." Jiraiya figured Naruto's will just wasn't strong enough yet. Perhaps putting him through a difficult trial would stimulate his potential.
Kakashi Hatake raised his hand, glanced at the old man and the young boy, and acted as a temporary referee. "Are you ready? Naruto? Jiraiya-senpai?"
"Let's begin!"
The ground under Jiraiya's feet instantly shattered. He shot forward with such speed that he kicked up a light breeze. Even Kakashi watched in surprise as Jiraiya rushed Naruto. A legendary Sannin of Konoha, and he was the one to attack first?
Boom!
Naruto only had time to see a burly figure appear in front of him before Jiraiya's fist struck his chest.
"Brat!" White hair fluttered in the wind. The Gallant Jiraiya appeared on the other side of Naruto in the blink of an eye. "A fight between us isn't like your graduation survival exercise. This is a battle where a slight mistake can cost you your life!" Jiraiya shouted sternly, kicking Naruto's shoulder and sending him flying.
In mid-air, Naruto gritted his teeth. The force sent him spinning, and he couldn't control his direction.
But Jiraiya had already caught up to him.
"Spiral... Shockwave!"
Naruto gathered a vortex of chakra in his palm and slammed it toward the ground. The force of the shockwave reversed his momentum, and he flipped neatly to land on his feet.
Naruto stood firm, gathering a Rasengan in each palm. Before they could fully form, he suddenly clapped his hands together and pushed the chakra out.
"Spiral Shockwave: Combine!"
A stream of blue chakra shot forward, destroying everything in its path. The Gallant Jiraiya, who was charging head-on, dodged it. Looking at the jutsu's power, he said with surprised uncertainty, "That technique... is it a masterpiece born from a failed Rasengan training?"
As another user of the Rasengan, having learned it from his student, Jiraiya had also researched other possibilities for the technique. During the high-speed rotation of the Rasengan, if a gap was created and the chakra released, it could indeed have a super-strong impact. However, this method was too dangerous. A slight miscalculation and the Rasengan would explode. Besides, Jiraiya's chakra reserves wouldn't allow him to waste energy like that.
But Naruto could do it, and even develop a new jutsu based on his own chakra advantage. This kid is too much like his father!
The chakra vortex in Jiraiya's palm gathered quickly. He laughed heartily at Naruto. "Brat, let me show you a real Rasengan!"
"..."
Naruto's expression finally tensed. Since learning the Rasengan, his strength had improved by leaps and bounds. As a user himself, he knew the high growth potential of the jutsu. Jiraiya had definitely been using it longer and must have researched more variations.
I have to be extra careful...
Naruto gathered a chakra vortex in his own palm. He kept his eyes locked on Jiraiya, watching his every move and paying close attention to the Rasengan forming in his hand.
If they both used Rasengan, the winner would be determined first by the amount and density of chakra, and second by any nature transformation within it. Theoretically, whoever attacks first, loses. You have to change the nature of your Rasengan based on the opponent's to have a chance at victory.
As a man who had personally witnessed the Wind Style: Rasenshuriken, Kakashi also knew the key to victory. "Jiraiya-senpai... Naruto... whose Rasengan development is higher? Whose jutsu is stronger?"
Wait! The Rasengan is no small jutsu! If the power of both their techniques is too strong, one of them will definitely be injured, and they might even both be severely wounded!
Kakashi's face grew solemn. "Jiraiya-senpai, clashing with jutsu like the Rasengan... isn't that too dangerous?"
"Kakashi, if you don't push the limit, you can never get stronger!" Jiraiya replied. Seeing that the Rasengan in Naruto's palm had successfully formed, his eyes narrowed and his face grew serious. "I guessed wrong... that kid has already learned the Rasengan!"
"But that's just perfect!" Jiraiya smiled, glanced at the Rasengan in his own hand, and flew towards Naruto. He wanted to see this kid's limit.
Kakashi saw Jiraiya rushing down with a small Rasengan and couldn't help but twitch the corner of his mouth. "Hey, hey, hey, Jiraiya-senpai, don't be overconfident!"
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Bonus:
Day 1:
Jiraiya: "Brat, I see you have a natural talent. How about learning a ninjutsu from me?"
Naruto: "What ninjutsu?"
Jiraiya: "What do you think of this Rasengan of mine?"
Naruto: "It's... alright, I guess?"
Jiraiya: "So, do you want to learn it?"
Naruto: "Fine."
Day 2:
Jiraiya: "First, I'll give you a water balloon..."
Naruto: "Pervy Sage, I've already developed the Wind nature transformation, as well as the more powerful Great Ball Rasengan. Just teach me how to add the nature transformation inside it..."
Jiraiya: "...Well..."
Naruto: "What?"
Jiraiya: "Brat, do you know who I learned the Rasengan from?"
Naruto: "???"
Day 3:
Konoha Morning News Headline:
Has Legendary Sannin Jiraiya Been Overrated? Is He Good at Teaching, or Just Picking Talented Students?
Konoha Morning News Press Release:
According to our sources, Jiraiya learned the Rasengan from his student Minato Namikaze many years ago but has been unable to master adding a nature transformation to it.
Recently, Jiraiya was seen using a new form of the Rasengan. Some have mentioned that he learned it from his other student, Naruto Uzumaki.
As we know, the copyright dispute over the Rasengan between Naruto Uzumaki and Minato Namikaze has just concluded in the Pure Land.
Does Jiraiya have an unknown connection to this? Stay tuned for our reporter's next story.