Dawn broke over the banks of the Naka River, and a cool breeze brushed across the water, sending ripples over its surface.
Shinichi stood atop a large boulder, his gaze calm. His usual irreverence was gone, replaced by an intensely serious expression.
Tsunade and Orochimaru stood opposite him. Sensing that Shinichi was more serious than ever before, they dropped their usual casual attitudes and waited attentively for the lesson to begin.
"Tsunade, Orochimaru." Shinichi's gaze swept over them, his voice steady and firm. "This training isn't just about teaching you the Rasengan. It's about helping you grasp the essence of chakra use."
Tsunade frowned slightly and asked in confusion, "Isn't the Rasengan just a ball of high-pressure, spinning chakra? As long as my chakra is strong enough, I should be able to use it."
Orochimaru looked thoughtful instead and spoke slowly. "No, Tsunade. If Shinichi takes it this seriously, it can't be just a 'simple' jutsu. Its true nature is probably far more complex than what we've seen."
Shinichi nodded. "Exactly. On the surface, the Rasengan seems to be pure destructive chakra power. But its real significance is that it represents ninjutsu in its purest form."
He held out his hand and slowly gathered chakra in his palm. A mass of blue chakra quickly formed and began spinning at tremendous speed, like a miniature storm. The chakra flowing within maintained a perfect balance, neither leaking out nor requiring any hand signs to control it.
"This jutsu requires no hand signs at all—which means you have to rely entirely on your own chakra control, without any outside assistance or jutsu mechanisms," Shinichi said slowly. "That's the Rasengan's first core principle—absolute chakra control."
As Tsunade watched the rapidly spinning sphere of light, her expression gradually grew serious. "So... if the chakra flow is even slightly off, the whole jutsu will collapse?"
Shinichi nodded and continued, "The second core principle—chakra stability."
He slowly raised his palm and gave it a slight shake. The Rasengan's rotation changed just a little, and the once-stable sphere immediately began trembling violently. A moment later, the chakra on its surface spun wildly out of control. The entire Rasengan burst in his palm, scattering into countless tiny blue specks of light that faded away.
"If you can't maintain its stability, the Rasengan will break apart prematurely. It might even explode in the user's hand," Shinichi said evenly. "That's why only people with exceptional control can learn it."
Tsunade clenched her fists, her eyes burning with eagerness. "Then what's the last core principle?"
Shinichi gave her a long look, his gaze sharp. "The third core principle—chakra compression."
He held out his hand again. This time, the chakra sphere in his palm was more concentrated than before, shrinking to half its previous size. Its pale blue color deepened, its light subdued rather than glaring, giving it an impression of immense stability.
"The more concentrated the chakra, the greater its power. The Rasengan has no added elemental nature. Its pure destructive power comes from taking chakra rotation and compression to their limits," Shinichi said slowly. "What you need to do is master all three perfectly."
Tsunade and Orochimaru exchanged a glance, their eyes alight with eagerness.
"Understood," they said in unison.
Shinichi took two water balloons from a nearby wooden bucket and handed them to Tsunade and Orochimaru. His tone was calm. "First, use chakra to create a whirlpool inside the water balloon. Make it burst through chakra rotation, not by crushing it with brute force."
Tsunade took the water balloon and gritted her teeth as she gathered chakra.
However, her naturally enormous chakra reserves caused her to pour in too much right from the start. The balloon suddenly swelled, then burst with a pop, spraying water everywhere and drenching her from head to toe.
Shinichi gave her a mild glance. "You're using too much force. Chakra control isn't a contest of explosive power, but of precision. Your chakra reserves are far beyond most people's, but without precise control, they'll only become your greatest burden."
Tsunade frowned and picked up another water balloon, her expression solemn.
Orochimaru, meanwhile, was entirely different. His chakra flowed calmly and precisely into the water balloon, forming layers of tiny whirlpools.
However, he was too slow, and the balloon showed no sign of bursting.
Watching his movements, Shinichi said calmly, "Your problem is... you're too cautious with your control, so the rotation isn't fast enough. The Rasengan needs rotation pushed to its limit, not a steady supply of chakra."
Orochimaru paused slightly, his eyes flickering as he considered Shinichi's words.
The two kept trying. Water balloons burst again and again as their attempts failed, but each failure gave them more experience. Gradually, they began to grasp the technique of chakra rotation.
Once they had mastered rotation with the water balloons, Shinichi brought out balloons filled with air and handed them over. "The next step is to compress your chakra into a stable state. Fill the balloon with chakra and make it expand, but don't let it burst."
Tsunade tried once. The instant she poured in chakra, the balloon exploded, covering her face in scraps of rubber. She took a deep breath, clearly realizing where the problem lay.
"I can't just add more chakra. I have to keep it stable..." Tsunade murmured to herself, adjusting her chakra flow. This time, she successfully filled the balloon with chakra and kept it stable.
Orochimaru quickly mastered the technique. With extremely fine chakra control, he slowly filled his balloon, pushing its surface tension to the limit without bursting it.
Shinichi nodded, showing a rare look of approval. "Very good. Your chakra control is improving faster than I expected."
"All right, Tsunade. It's getting late. Orochimaru and I should head back." Shinichi stretched and gave her a relaxed smile, his casual gaze holding a touch of warmth.
He patted Orochimaru's shoulder and turned to leave. Looking back, he waved, his lips curling into their familiar lazy smile. "See you tomorrow. Don't miss us too much."
With her hands on her hips, Tsunade watched them walk away. She pursed her lips and gave a little huff, but couldn't help smiling faintly.
Night had fallen deep over the Senju Clan's residence, where lamplight illuminated the solemn atmosphere inside.
Senju Toka stood quietly before Tobirama Senju, respectfully reporting her recent observations of Uchiha Shinichi and Tsunade.
"...Tsunade and Shinichi have been growing closer. Not only do they often spend time together, but Shinichi has also been teaching her and Orochimaru an entirely new jutsu." Senju Toka paused and looked at Tobirama with a conflicted expression. "That jutsu requires no hand signs. It can be performed through chakra control alone. Shinichi calls it—the Rasengan."
At the unfamiliar name, Tobirama Senju's cold, blade-sharp eyes shifted slightly. He set down the document in his hand and looked up at Senju Toka. "A jutsu without hand signs? Explain."
Senju Toka nodded and gave a detailed account of Shinichi's explanation of the Rasengan's three core principles—chakra rotation, stability, and compression—as well as the entire process of Tsunade and Orochimaru's training. She did not even leave out Shinichi's meticulous approach to teaching.
As she spoke, Tobirama Senju's expression grew increasingly grave, his fingertips unconsciously tapping the desk.
Even with all his knowledge, he had to admit that the Rasengan Shinichi had developed went completely beyond the current theoretical understanding of ninjutsu.
No hand signs, pure chakra control, and destructive power pushed to the limit.
A jutsu like that held immense promise!
"...Shinichi is only five years old, yet he can create such an advanced jutsu?" Tobirama asked in a low voice, his tone carrying a rare mix of astonishment and contemplation.
Senju Toka nodded, a complicated emotion flickering in her eyes. "Yes, Tobirama. I saw it myself. He has already mastered the complete form of this jutsu and is teaching it to Tsunade and Orochimaru."
Tobirama fell silent for a moment, considering something. Then he spoke, his gaze deep. "This isn't merely a jutsu. It's a breakthrough in the entire ninjutsu framework... if it can be refined further, the Rasengan's power could rival A-rank jutsu, or even higher."
His fingers tightened slightly, and his brow furrowed. Uchiha Shinichi... this boy was far more troublesome than he had expected.
This was not simply talent. It was—creativity.
Recalling his battles with Madara Uchiha, Tobirama knew full well that talent alone was nothing to fear. The truly frightening ones were those who could advance the entire ninjutsu framework. Hashirama, Madara Uchiha... even he himself had been such a person.
And now, Shinichi possessed that same potential?
Watching Tobirama's expression, Senju Toka asked tentatively, "Tobirama, should we increase our surveillance of Shinichi? Or... take action before it's too late?"
Tobirama slowly closed his eyes, his fingertips tapping softly against the desk.
Several seconds later, he opened his eyes, his gaze piercing. "No. Keep observing him. Don't alert him."
He continued in a low voice, "Uchiha Shinichi has shown no hostility so far. On the contrary, he's training Tsunade and Orochimaru. If he's willing to become an asset to Konoha, there's no need to reject him."
Senju Toka paused, clearly somewhat surprised.
Tobirama added quietly, "But... if his growth threatens Konoha's balance... we must be ready to respond at any moment."
Senju Toka lowered her head. "Yes, Tobirama."
The night deepened. Lamplight illuminated Tobirama's pensive face as he quietly gazed at the stars outside the window, countless thoughts running through his mind.
Uchiha Shinichi... before long, that name would likely become one Konoha could no longer afford to ignore.
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