Senba fell silent and considered the offer. He had replicated the Rasengan thanks to his max-level mastery of shape transformation, so in a way, he had created it himself.
Although the true inventor was the future Minato, right now, Senba was the only one who knew the technique.
Having it recorded in the Scroll of Seals meant three A-Rank ninjutsu, a five-million-ryo reward, and a chance to learn an S-Rank jutsu. Plus, he could still teach the Rasengan to whomever he pleased. It was a good deal.
He could chalk it up as a contribution to the village. Besides, Konoha... would be his one day anyway.
"Alright, let's go to the Hokage Building tomorrow to record it. " Senba eventually said.
A smile spread across Tsunade's face as she reached out and ruffled his hair. "I knew you'd agree."
"Okay, we can talk about that later. For now... it's time to teach you Super Strength."
Tsunade took two steps back, then raised her right fist and slammed it into the ground.
Boom!
The ground shook with a deafening crash. The hard-packed earth of the training ground shattered instantly, with spiderweb cracks shooting out from the point of impact. Dust and gravel flew into the air.
When it all settled, a crater nearly two meters wide and half a meter deep had appeared.
Standing off to the side, Senba couldn't help but swallow. The force of that punch was easily on par with his Rasengan. No wonder Jiraiya was so terrified of Tsunade; if a punch like that landed, you wouldn't just have broken bones—you'd be turned to paste.
Tsunade pulled her fist back and looked at him smugly. "See that?"
Senba nodded.
She grinned, satisfied with his terrified expression, and began to explain. "The principle behind Super Strength is simple, really. It's all about precise chakra control. You focus your chakra into one part of your body and then release it all in a single instant."
She paused, continuing, "Like you just saw, concentrate it in your fist, and you get a punch like that." If you focus it on your foot, it's called the Heavenly Foot, and it's just as devastating."
Senba listened intently. Tsunade walked over and took his wrist.
"You created a seal-less, A-Rank jutsu like the Rasengan and mastered the Mystical Palm Technique on your first try. Your chakra control is already better than most jonin."
Her own chakra flowed into Senba, guiding the energy within him.
"Memorize this pathway and concentrate your chakra right here on your fist..." she instructed, tapping his knuckles. "Then, the moment you make contact, unleash it all at once."
Senba closed his eyes, focusing on the flow of chakra inside him until the pathway was burned into his mind. He opened his eyes, walked over to a clear spot, and took a deep breath.
'With Max level chakra control, it shouldn't be hard to replicate.'
Mimicking Tsunade, he raised his fist and slammed it into the ground.
Boom!
The ground cracked instantly. While it wasn't as powerful as Tsunade's punch, fissures still spread out over half a meter wide.
Senba looked down at his fist, then at the cracks, frowning slightly. The difference in power felt like a full-force Rasengan versus ten percent force.
Tsunade walked over, nodding with satisfaction. "Not bad. You've already got the hang of Super Strength."
She crossed her arms. "Your chakra reserves aren't as big as mine, so of course it's going to be a bit weaker. That doesn't matter. As your reserves grow, the power will too."
A wistful look crossed her eyes. "If you had as much chakra as my grandfather, you could probably take down a Tailed Beast with a single punch."
Senba's eyes widened. The Tailed Beasts were considered living natural disasters, each with power rivaling a Kage.
Knocking them down with one punch? Even Hashirama couldn't do it.
"But that's for later," Tsunade said, snapping out of it. "Come on, let me show you the Heavenly Foot."
She lifted her right foot and stomped down hard.
Boom!
Another loud crash, and an identical crater formed in the ground.
"Concentrate the chakra right here on the ball of your foot," she said, pointing. "The release is the same as with your fist. Give it a try."
Senba nodded, found a new spot, lifted his foot, and stomped.
Boom!
Cracks appeared. It still wasn't as strong as Tsunade's, but he had succeeded again.
Tsunade looked from the new cracks back to Senba, her eye twitching.
One try. He got it in one try.
This kid... how was he so talented? It had taken her days of practice to master Super Strength.
Senba, on the other hand, was secretly pleased with his results. Max-level chakra control was the same as max-level talent, since every jutsu relied on it.
He remembered how he used to burn his own mouth practicing the Great Fireball Technique. But ever since the system upgraded his control, learning the Phoenix Sage Fire Technique was effortless; he could do it on the first try without a single scorch mark.
That was the terrifying power of max-level talent. As long as he had the time and didn't need a new chakra nature, he could master most B- and A-rank jutsu quickly.
Snapping out of his thoughts, Senba looked and asked. "Sensei, what's next?"
"That's enough for today." Tsunade's mouth twitched. She turned and walked out of the training ground, calling over her shoulder, "If I teach you any more, I think my jealousy might make me hit you."
"Practice the Mystical Palm and Super Strength on your own. I'll take you to the Hokage Building tomorrow morning."
Senba blinked, then a small smile crept his lips. He pulled up his system panel. His overall strength had successfully climbed to A-, putting him at the level of a Special Jonin.
The evaluation was clear: learning so much ninjutsu was what pushed his rating up a level to special jonin standards. But even if he overcame his lack of combat experience, he couldn't reach the level of a full Jonin. His B-rank chakra reserves restricted his growth.