A secluded training ground, this was Aoshi's usual place for private training. At the moment, one of Aoshi's shadow clones stood with Minato on the field.
"Aoshi-nii, what did you need me for?"
"I've recently developed a new jutsu," Aoshi replied. "Once Mikoto and Kushina arrive, I'll teach it to all of you together."
Ten days had passed since the end of the preliminary round. During that time, Aoshi had finally succeeded in creating the Rasengan.
At first, he thought it would only take a day or two. But once he began attempting it himself, he realized it was far more difficult than expected.
Now, he finally understood why Minato in the original story needed three years to develop the Rasengan.
Minato was visibly surprised. He wasn't an inexperienced ninja—he fully understood how hard it was to develop a jutsu from scratch.
Though he'd always been called a genius, even he had once dreamed of creating his own jutsu, only to abandon the idea because the challenge proved too overwhelming.
"But, Aoshi-nii… this is your original jutsu. Are you sure it's okay for me to learn it?"
In the shinobi world, there was no such thing as teaching without distinction.
A self-created jutsu wasn't something one casually shared—unless the other person was a disciple, or close as family. Once a jutsu was leaked, it could easily be studied and exploited for weaknesses.
Aoshi, however, just smiled. "You already call me 'nii'—why wouldn't it be okay?"
"Thank you, Aoshi-nii." Since Aoshi had said that, Minato no longer protested, quietly committing the favor to heart.
Before long, Mikoto and Kushina also arrived.
"Alright, Aoshi, we're all here. Go ahead and say what you needed to."
Aoshi nodded, stretched out his right hand, and began concentrating chakra into his palm. Before long, a blue spinning orb of chakra had formed.
"This is the new jutsu I created—the Rasengan."
The three of them were stunned. Even Minato, who had known beforehand, was still shocked. After all, Aoshi had never mentioned that the Rasengan was a non-hand seal jutsu.
The norm in the ninja world was to use specific hand signs to mold chakra and form a technique.
Those with superior chakra control could reduce the number of hand signs or perform them one-handed—but a jutsu that required no hand seals at all was extremely rare.
Most ninja would go their whole lives without seeing one. And if someone truly mastered a jutsu that could be activated without hand signs, it would provide an immense advantage in combat.
Without pausing to explain, Aoshi maintained the Rasengan and walked toward a large tree.
With a gentle push, he pressed the Rasengan into the trunk. The massive tree—wide enough for two people to wrap their arms around—was instantly pierced, leaving a hole the size of a football.
The tree then split in half at the trunk and exploded into a flurry of wooden splinters under the force of the jutsu. If a ninja were caught off guard by this attack, they'd be killed instantly.
"Amazing!" Kushina exclaimed instinctively.
Hearing her reaction, Aoshi smiled. "Actually, the Rasengan is especially suited to someone like you—with a huge chakra reserve. It'll let you unleash your full potential."
"Then hurry up and teach me! I can't wait!"
Aoshi then began explaining the principles behind the Rasengan, as well as the step-by-step training method. All three were highly gifted ninja, so they picked it up quickly.
But the fastest among them was Mikoto.
Watching her master the Rasengan right after Aoshi's explanation, Kushina couldn't help but feel a little envious. "Must be nice having the Sharingan. One look and you've already learned a new jutsu."
If she had the Sharingan, learning sealing techniques would've been far less troublesome.
Mikoto rolled her eyes. "You really think the Sharingan is all-powerful? If it were that simple, every Uchiha would know thousands of jutsu."
The Sharingan could indeed copy techniques—but not without limits. It couldn't replicate other bloodline-limit or some complex jutsu. And unless the user had the right chakra nature, even copied jutsu couldn't be performed.
In truth, they could copy the jutsu, but not necessarily use them.
That's why Hatake Kakashi—who later gained a Sharingan—earned the nickname "Copy Ninja." He possessed the chakra of all five natures.
Most Uchiha were specialized in Fire Release.
"But it's true that having the Sharingan does make learning jutsu a lot easier."
That much, Kushina admitted.
For Uchiha with the Sharingan awakened, learning jutsu was indeed faster. Even starting from scratch, they could grasp a new chakra nature with relative ease.
In theory, the Uchiha clan could master thousands of techniques per person. But there was no need to.
For one, they didn't have nearly enough chakra to use that many jutsu in battle. And most jutsu lacked practical use.
Once a ninja reached elite Jonin or even Kage level, simply learning more jutsu wouldn't significantly boost their strength. Only S-rank forbidden jutsu might make a difference.
So instead of learning everything, it was better to specialize in one thing.
"Though the Rasengan is an A-rank jutsu, it shouldn't be too hard for you, Kushina. If you don't take training seriously, Minato's going to surpass you."
Seeing Minato already practicing the third stage with the rubber ball, Kushina focused herself again. She wasn't about to let Minato pull ahead.
Watching the two of them train diligently, Aoshi pulled Mikoto aside. "Mikoto, the Rasengan can actually be developed further. You can add elemental chakra nature into it."
He explained the next stage of development to her.
As he spoke, Aoshi demonstrated Water Release: Rasengan.
Unlike Naruto's Wind Release variant, Aoshi specialized in Water Release. After all, he'd inherited top-tier water-style talent from Hanzō the Salamander.
Under Mikoto's amazed gaze, Aoshi infused water chakra into the Rasengan. The blue orb immediately changed, rippling like flowing water.
"You specialize in Fire Release, Mikoto. You could try developing Fire Release: Rasengan."
"You're incredible, Aoshi. To create something this powerful on your own..." Mikoto's admiration was genuine.
…
In the blink of an eye, another twenty days passed. Within that time, Kushina and Minato had both mastered the Rasengan.
When Aoshi arrived at the arena for the final round of the Chūnin Exams, the stands were already packed.
Not just with Konoha shinobi and civilians—but nobles and daimyō from various nations.
Meanwhile…
In Hozuki Castle—
With assistance from Hidden Cloud, the Grass Village had finally gathered enough chakra to open the Box of Ultimate Bliss.
Standing before the massive, ominous box, the Grass Village Chief trembled with anticipation.
"Box of Ultimate Bliss—grant my wish. Destroy Konoha!" As his voice echoed out, a terrifying monster burst forth from the box, launching itself in the direction of Konoha.