Jiraiya felt that the boy, Uchiha Gen, was truly far too honest.
"No matter what, it's just an incomplete ninjutsu right now."
"I imagine that even when it's finished, you two wouldn't ever use it against me, right?"
Uchiha Gen smiled as he spoke.
The appearance of the Rasengan was, in a sense, originally derived from this master and disciple duo.
If the two of them truly benefited from the Rasengan, given their noble personalities, they would surely remember this favor.
"According to what Senior Gen said, the only thing missing for the final perfection of this technique is how to guide its power with the correct rotation method."
Minato Namikaze tried to condense and release Chakra in his palm.
Perhaps because this technique was originally invented by him in the original timeline and was the one that suited him best, he managed to condense a blue-and-white rotating Chakra sphere in his palm instantly during his first attempt.
However, due to his currently insufficient control over Shape Transformation, the sphere only lasted for two seconds before flickering out.
"Well, a technique performed without the guidance of hand seals will inherently have its Chakra control affected."
"It won't have the characteristics of an elemental nature either, so it's normal for the power to be weaker."
"To release the true power of this Chakra, one must achieve physical properties manifested after training Shape Transformation to a certain level."
Jiraiya stroked his chin and pondered, then scratched his head.
"How about first trying to rotate the Chakra according to the pattern of the hair whorls on your head? That might make it spin a bit faster."
Jiraiya looked down at Uchiha Gen's head.
Although the boy was an orphan, being born into the Uchiha meant he didn't lack nutrition.
His height wasn't low for a thirteen-year-old, already standing slightly over 1.6 meters.
However, Jiraiya was tall and sturdy, standing at over 1.9 meters, so his line of sight could clearly see the top of Gen's head.
"That sounds like some kind of superstitious folk remedy," Minato remarked, scratching his own head.
"Well, you have two whorls, and both are counter-clockwise, so the rotation must be to the left."
"But Senior Jiraiya, I am already rotating it to the left," Uchiha Gen pointed to the sphere in his palm.
"No rush, let's look at Minato's... hmm... also two whorls."
"Is the folk rumor true that people with two whorls on their heads are smart?"
"But Minato's two whorls are in different directions."
"Could it be that they need to rotate in two directions simultaneously? Forget it, let's just try whatever works!" Jiraiya said, sounding distressed.
Minato Namikaze suddenly looked up sharply, staring at Jiraiya with a look of realization.
"As expected of Jiraiya-sensei, to think of such a method! It might actually work!"
"Simultaneous rotation? Irregular rotation? Letting the Chakra explode with power in a reverse impact?"
"I've tried that before, but wouldn't that make it even more uncontrollable?" Uchiha Gen frowned suspiciously.
In the original series, irregular rotation was mentioned, but it was never explicitly stated how to achieve it while keeping the Chakra sphere stable.
In practice, if the interior was truly uncontrollable, the Rasengan wouldn't be able to maintain itself; it would simply explode.
If one wasn't careful, the power of the explosion might even injure the user's hand.
The key to the final step had to be right here.
Minato Namikaze gave a slight smile.
"Senior Gen is being too clever for his own good."
"We only need the Chakra to be able to collide irregularly, rather than truly controlling the trajectory of the Chakra haphazardly."
"And to achieve this, isn't it exactly what Jiraiya-sensei just said? Simultaneous rotation."
"Simultaneous rotation... performing it twice at the same time? Or..."
Uchiha Gen murmured softly, and images of Uzumaki Naruto using the Rasengan suddenly flashed through his mind.
Most of the time, Naruto relied on the help of Shadow Clones to multitask and form the sphere.
Even later, as Naruto in his Nine-Tails Chakra Mode, he still needed to manifest two more Chakra arms to form it.
For one Rasengan, it had to be formed through multiple rotations simultaneously.
The secret of simultaneous rotation should be one force controlling a portion of the Chakra clockwise, while the other force controls the remaining portion counter-clockwise.
One inside and one outside, one containing the other, layered upon each other.
Only then can stability be maintained, and when power needs to be released, the two directions can collide to enter an irregular state.
And it's irregular rotation to a certain extent, not a truly chaotic mess.
Thinking of this, Uchiha Gen focused his gaze on his palm.
His excellent Chakra control ability came into play at this moment.
Gen tried to layer the Chakra sphere into inner and outer layers, with the inner layer spinning clockwise and the outer layer counter-clockwise, then merged them.
He also added an inward rotation on the outermost layer to ensure the Chakra wouldn't leak due to the irregular internal friction.
Soon, a peaceful yet distinct humming sound gradually rose and finally stabilized.
And what stabilized along with it was the azure Chakra sphere in Uchiha Gen's hand.
It was blue on the outside and white on the inside, with white lines representing Chakra trajectories darting irregularly within.
It was beautiful, translucent, and filled with a unique aesthetic, yet it contained terrifying energy.
"Rasengan—this technique is finally a success!" Uchiha Gen grinned.
With Uchiha Style Swordsmanship and the Rasengan, his lethality in close-quarters combat would increase significantly.
Why was the Minato Namikaze of the original timeline so strong that enemies were ordered to flee on sight?
The Flying Thunder God was certainly the most important factor, but paired with the Rasengan—a seal-less, instant-cast ninjutsu—it perfectly showcased the utility of space-time movement.
In just an instant, before an opponent could react, he would teleport over and slam a Rasengan into them.
While there were certainly powerhouses who could tank a Rasengan with their bare bodies, most of them were top-tier experts standing at the apex of the Ninja World.
Most ninjas would undoubtedly die if they took a direct hit from it.
Any ninja below the Jonin level would be killed instantly when facing a prime Minato.
For Uchiha Gen, although he didn't know the Flying Thunder God yet, having swordsmanship in one hand and the Rasengan in the other meant that while the enemy focused on defending against the sharp sword, he could suddenly unleash a Rasengan at any moment.
"Rasengan... this technique already has a name."
"But I have a better one: 'Halo Hair Whorl-Inspired Uchiha Gen Dual-Directional Rotating Sphere'!"
Minato Namikaze held up a finger with a dorky, proud expression.
"Hmm, that is indeed a great name," Jiraiya nodded in agreement.
"Jiraiya-sensei, do you really think so too?"
"The name Rasengan is indeed very appropriate. Minato, naming things isn't for you. Let's just forget about it in the future."
Jiraiya teased his disciple with a laugh.