In the corporate world, there is a concept known as "compound interest." It is the principle that small, consistent gains, when reinvested, generate exponential growth over time. Albert Einstein reportedly called it the eighth wonder of the world.
Nanami Kento, aged six, decided that Einstein would have made a terrifying ninja.
One month had passed since his enrollment at the Academy. To the casual observer, Nanami was merely the top student—a quiet, diligent boy who sat by the window, answered questions correctly, and ate balanced lunches.
To the universe, however, he was a glitch in the system.
The "one month" was a lie. Thanks to the acquisition of the Shadow Clone Jutsu—and subsequently, the Multi-Shadow Clone Jutsu—Nanami had not lived one month. He had lived approximately five.
The second bet with Tsunade had been even easier than the first. He had simply wagered that she couldn't go a full twenty-four hours without yelling at Jiraiya. She lasted forty-five minutes. The payout was the Multi-Shadow Clone scroll, which she had "borrowed" from the Senju archives to prove a point about her family's library size.
With the ability to summon four clones at once without fainting, Nanami's productivity had skyrocketed.
While the original Nanami attended the Academy, maintaining his cover and social network, Clone 1 was devouring Fuinjutsu theory. Clone 2 was in the woods, conditioning his body. Clones 3 and 4 were engaged in a hellish, experimental project that Nanami had dubbed "Project Spiral."
The Rasengan.
It was an A-rank jutsu created by the Fourth Hokage. It relied on pure shape transformation. No hand signs. Just raw, rotating power. Nanami knew the theory: rotation, power, containment. He remembered the water balloon and rubber ball training method from the anime.
It should have been easy.
It was not.
For the first week, Clone 3 and Clone 4 did nothing but pop water balloons. They went through hundreds of them. The backlog of popped rubber and soaked clothes was immense. The rotation required to burst a balloon with chakra was chaotic; controlling it with a six-year-old's hands was like trying to herd cats with a leaf blower.
But they persisted. The memories of every popped balloon, every flicker of rotation, filtered back to Nanami every evening. The headaches were blinding, but the progress was undeniable. He was currently at the final stage—containment. Keeping the swirling storm within a stable sphere.
But today, the clones were dispelled. Today was for the original.
The sun was high over Training Ground 4. The air was still, heavy with the humidity of late summer.
Nanami stood in the center of the clearing. His shirt was soaked through with sweat, clinging to his back. His breathing was a rhythmic hiss, in and out through his nose.
He assumed the stance.
Feet rooted. Knees bent. Spine aligned with the axis of the earth.
He brought his hands together in a prayer motion. It was a simple gesture. Religious, yet martial. Soft, yet hard.
"One."
His right fist shot out.
It wasn't a punch. It was a lance of intent.
In the beginning, the motion had taken him ten seconds to perform correctly—the prayer, the chambering, the strike, the return. It was clumsy.
Now, after a years of practicing it thousands of times a day—both physically and mentally through clones—the time had compressed.
Clap. Thrust. Return.
Four seconds.
To a Jonin, four seconds for a punch was an eternity. But for a six-year-old performing a complex ritualistic motion that channeled gratitude into violence? It was terrifyingly fast.
Clap. Thrust. Return.
The air cracked. A leaf falling ten feet away split down the middle, severed by the pressure wave of the fist.
Nanami closed his eyes. He felt the "Ultra Instinct" passive humming in the back of his skull. It wasn't a voice; it was a radar. It mapped the clearing in 360 degrees.
He felt the beetle crawling on a stump to his left. He felt the wind shifting the branches of the oak tree.
And he felt the three heartbeats hiding in the bushes to his south.
Nanami finished the punch. He lowered his hands, exhaling a long, white plume of breath.
"You know," Nanami said to the empty clearing, his voice calm but projecting clearly. "Stealth is a required course in the second year. Currently, you three sound like a herd of elephants negotiating a treaty with a shrubbery."
Silence from the bushes.
Then, a rustle.
"I told you he knew!" a loud whisper hissed.
"Shh! Maybe he's bluffing!"
"YOUTH CANNOT BE HIDDEN!"
Nanami turned his head toward the noise. "Come out. You are disturbing the concentration of my training."
The bushes parted.
Three figures tumbled out.
Tsunade Senju, looking dusty and annoyed, brushed leaves out of her hair. Jiraiya, holding a bag of chips, stumbled after her. And Might Duy, grinning and giving a thumbs up, brought up the rear.
"We weren't hiding!" Tsunade claimed, crossing her arms defensively. "We were... observing. Tactical reconnaissance."
"You were spying," Nanami corrected. "Why?"
"Because you disappear every day after school!" Jiraiya shouted, crumbs flying from his mouth. "We thought you had a secret girlfriend! Or a secret stash of food! But no, you're just out here punching the air like a weirdo."
"It is not 'punching the air'," Duy interjected solemnly. "It is a conversation with the universe! I can feel the passion in every strike, Kento! It is beautiful!"
Nanami sighed, grabbing his towel and wiping his face. "If you wanted to watch, you could have just asked. I have no secrets. Just hard work."
"Can we stay?" Tsunade asked, her eyes lingering on the split leaf on the ground. She had seen it. She knew what wind pressure meant. "We won't disturb you."
Nanami looked at them. The future Sannin and the future Eternal Genin. His cohort.
"Fine," Nanami agreed. "But sit silently. If Jiraiya eats chips loudly, I will remove him from the premises."
"Deal," Tsunade said, grabbing Jiraiya by the ear and dragging him to a log. Duy happily sat in a squat position, his back straight, turning observation into a workout.
Nanami returned to the center.
Focus, he told himself. Ignore the audience. The audience is irrelevant. Only the prayer matters.
He resumed.
Clap. Thrust. Return.
Clap. Thrust. Return.
Tsunade watched with wide eyes. She had grown up watching her Granduncle Tobirama train. She knew what high-level taijutsu looked like. It was usually fast, brutal, and efficient.
This was different.
Nanami's movements were... heavy. Every time his hands came together in prayer, the atmosphere seemed to tighten. And when he punched, it didn't look like he was throwing a fist; it looked like he was throwing a mountain. The rhythm was hypnotic.
Four seconds, she counted mentally. Every single time. Exact precision. He's not getting tired. He's getting faster.
Jiraiya, initially bored, had dozed off against the tree, a snot bubble expanding and contracting with his breath.
Duy was staring with tears in his eyes, whispering "Youth" every time Nanami struck.
An hour passed.
Nanami completed his set. He didn't collapse. He didn't gasp. He simply stopped, bowed to the clearing, and turned to his friends.
"Done."
Duy leaped up from his squat. His legs should have been jelly, but he bounced with energy.
"Kento!" Duy shouted, stepping forward. "That was inspiring! The sweat! The focus! My blood is boiling! Please! Spar with me!"
Nanami looked at the older boy. Duy was a powerhouse of stamina. His technique was raw, unpolished, and frankly dangerous to himself, but his strength was undeniable.
"Pure Taijutsu?" Nanami asked.
"Of course! Fists are the language of men!"
Nanami nodded. He walked to the center of the ring. "Very well. Ready when you are."
Duy didn't wait. "DYNAMIC ENTRY!"
He launched himself forward with a flying side kick. It was fast—faster than any Academy student had a right to be.
Nanami didn't panic. His perception slowed the world down. He saw the trajectory of Duy's foot. He saw the opening in Duy's groin.
Block, Nanami decided. He needs to feel the wall.
Nanami raised his forearm. He didn't brace; he flowed into the impact.
Thud.
Duy's kick connected. Nanami slid back a few inches, his boots carving grooves in the dirt, but he didn't buckle.
"Strong," Nanami complimented.
Duy landed and unleashed a flurry of punches. Left, right, hook, uppercut.
Nanami wove through them. He dodged to the left by tilting his head. He parried the right with a soft palm deflection. He ducked the hook.
It was like watching water flow around a rock. Nanami wasn't fighting force with force; he was redirecting it.
Now, Nanami thought.
Duy overextended on a straight punch. Nanami stepped inside his guard.
He placed a palm on Duy's chest.
He didn't push. He struck. A short, sharp burst of kinetic energy.
"Hah!"
Duy gasped as the wind was knocked out of him. He stumbled back, tripped over his own feet, and landed on his backside.
Nanami stood over him, hand extended. "Good fight, Duy. Your speed has improved, but you telegraph your kicks by tensing your shoulders."
Duy laughed, grabbing Nanami's hand and pulling himself up. "Thank you, Kento! I will work on my shoulders! You are strong! Like a fortress!"
"What's all the racket?"
Jiraiya blinked awake, wiping drool from his chin. He saw Duy dusting himself off. "Did bowl-cut lose? Hah! As expected."
Jiraiya stood up, stretching. He smirked at Nanami. "Alright, pretty boy. You got lucky against Duy. But my style is unpredictable. I'm the future Sage, remember?"
Nanami looked at Jiraiya. "You were asleep three minutes ago. Your muscles are cold. You will cramp."
"Shut up and fight!"
Jiraiya charged. He tried a low sweep, aiming to knock Nanami off balance.
Nanami simply jumped. He hovered in the air for a second, watching Jiraiya's leg pass harmlessly beneath him.
As he came down, Nanami landed gently on Jiraiya's back.
"Oof!" Jiraiya grunted as the weight drove him into the dirt.
Nanami stepped off him casually. "Pinned. You lose."
Jiraiya pounded the ground. "That doesn't count! You stepped on me!"
"In a war, the enemy will do significantly worse than step on you," Nanami lectured. "Get up. You left your entire back exposed."
"Next time!" Jiraiya swore, crawling away to sulk.
Then, there was movement from the log.
Tsunade stood up.
She didn't shout. She didn't announce her move.
She walked into the circle. Her golden eyes were focused. There was no gambling addiction here. No bratty princess. Just a Senju.
"My turn," she said.
Nanami straightened his posture. He sensed it instantly. Her chakra was flaring. Unlike the boys, Tsunade had perfect control. She was channeling strength into her limbs.
"Come," Nanami invited.
Tsunade moved.
She wasn't as fast as Duy, but she was heavier. Every step cracked the ground. She threw a straight punch at his face.
Nanami dodged, but he felt the wind of the fist brush his cheek. It stung.
If that connects, I lose teeth, he noted.
She followed up with a kick to the ribs. Nanami blocked with both arms.
CRACK.
The impact rattled his bones. He was sent skidding back three meters. His forearms throbbed.
"Serious, huh?" Nanami muttered, shaking out his arms.
"You're holding back," Tsunade accused, advancing on him. "You played with them. Don't play with me."
"Understood."
Nanami's expression shifted. The boredom vanished. His eyes sharpened.
Tsunade attacked again—a downward axe kick.
Nanami didn't block. He stepped into the attack. Before her leg could generate full momentum, he jammed his shoulder into her thigh, disrupting the kinetic chain.
Tsunade grunted, off-balance.
Nanami spun. He swept her standing leg.
Tsunade fell, but she twisted in the air, landing on her hands and springing back like a cat. She launched herself at him again, a flurry of strikes.
Nanami entered the Zone.
Left. Right. Duck. Weave. Parry.
He deflected her fists with the minimum amount of force required. He was a ghost. Every time she thought she had him, she hit empty air.
Tsunade was getting frustrated. Her breathing was ragged. She wound up for a massive haymaker, pouring chakra into her fist.
Big mistake, Nanami thought.
He waited until the last possible microsecond.
As her fist came toward his face, he dropped to one knee. The punch sailed over his head.
Nanami placed his palm on her stomach.
He didn't use the Rasengan. He didn't use chakra. He just pushed, using her own forward momentum against her.
Tsunade flew backward. She tumbled across the grass, rolling twice before coming to a stop on her back, staring up at the darkening sky.
Silence returned to the clearing.
Nanami stood up, brushing dirt from his knees. He walked over to her.
She was breathing hard, staring at the clouds. She looked angry, but also... impressed.
Nanami extended a hand.
"Are you intact?" he asked.
Tsunade looked at his hand. She sighed, the anger draining away. She grabbed it.
"Yeah," she grumbled as he pulled her up. She dusted off her pants. "You're annoying, you know that? You fight like... like water. It's frustrating."
"It is efficient," Nanami corrected.
She looked at him, really looked at him. "That punch you were doing earlier. The prayer thing. And the way you move. It's not Academy style. Who taught you that?"
Nanami walked over to his water bottle and took a long drink. He passed it to her. She drank gratefully.
"No one taught me," Nanami said. "I read about a man once. A man who spent years in the mountains, doing nothing but throwing one punch. Day after day. Year after year. Until he transcended the concept of punching."
The three children gathered around him. Even Jiraiya was listening now.
"Why?" Duy asked. "Why just one punch?"
Nanami looked at his hands—hands that were slowly becoming weapons.
"Because repetition is the mother of perfection," Nanami said softly. "There is a saying I like to live by."
He looked at them—the future legends of Konoha.
"I fear not the man who has practiced 10,000 kicks once," Nanami quoted, his voice carrying the weight of a teacher. "But I fear the man who has practiced one kick 10,000 times."
Tsunade's eyes widened. Jiraiya frowned, trying to process the math. Duy looked like he had just seen God.
"One kick... ten thousand times..." Duy whispered, tears streaming down his face again. "THAT IS THE ESSENCE OF YOUTH! I WILL DO 10,000 SQUATS TONIGHT!"
"Please don't," Nanami sighed. "You will get rhabdomyolysis."
Tsunade stayed silent for a moment, absorbing the words. "So that's why you do the prayer. You're trying to perfect that one motion."
"I am trying to remove the unnecessary," Nanami corrected. "The doubt. The hesitation. The lag between thought and action. When I punch, I do not want to think 'punch'. I want the punch to simply exist."
Tsunade nodded slowly. She looked at him with a new level of respect. He wasn't just a smart kid or a lucky gambler. He was a martial artist.
Then she grinned. "Anyway, tomorrow is a holiday. No Academy."
"I am aware. I planned to sleep until noon."
"Cancel that plan," Tsunade ordered. "My grandmother wants to meet you."
Nanami froze.
Grandmother.
Mito Uzumaki. The wife of Hashirama. The Jinchuriki of the Nine-Tails. The greatest Fuinjutsu master alive.
"Mito-sama wants to meet... me?" Nanami asked, keeping his voice steady despite the internal alarm bells ringing.
"Yeah," Tsunade shrugged casually. "I might have mentioned that you learned the Shadow Clone jutsu in a day. And that you're obsessed with sealing scripts. She got curious. She invited you to lunch."
Nanami closed his eyes.
Of course, he thought. The Sannin leak information like a broken faucet. I taught myself an A-rank kinjutsu and a B-rank forbidden technique, and now the most powerful woman in the village wants to audit me.
It was a trap. Or an interview. Or both.
But it was also an opportunity. If he wanted to master Fuinjutsu, there was no better teacher in history than Mito Uzumaki.
"I see," Nanami said, opening his eyes. He adjusted his collar, his corporate persona sliding back into place. "Lunch with the Uzumaki matriarch. It would be rude to decline."
"Great!" Tsunade beamed. "Come to the compound at noon. Don't be late. And wear something nice. Grandma hates sloppy people."
"I am never sloppy," Nanami replied affronted.
"See ya, Kento!"
The three of them left—Tsunade leading, Jiraiya complaining about his back, and Duy already starting his squats as he walked.
Nanami stood alone in the darkening training ground.
He looked at his fist.
Ten thousand punches, he thought. And tomorrow, I have to shake hands with a legend.
He picked up his bag.
Better get some rest. Tomorrow is going to be a high-pressure workday.