In this era, there weren't many people Uchiha Gin was familiar with, and most of them didn't even have a chance to learn the basics of internal energy.
After all, imagine trying to convince already capable ninja that a new secret technique could enhance their power.
They'd have to be crazy to believe it.
Only this small group was gullible enough.
Gin casually popped a piece of pastry into his mouth, the sweetness spreading and filling his heart with pure happiness.
"So sweet."
Just as he was about to grab another piece, a cat paw landed firmly on the back of his hand, stopping him.
A pair of bright blue cat eyes locked onto Gin's, accompanied by a sharp "meow."
"Where's your promise?" the cat seemed to ask.
"Where's your stretcher?" Gin shot back.
"What are you even talking about?"
The little cat lunged at him, claws flashing in a frenzy, but Gin easily pinned it down on the table with one hand, holding it there as it struggled.
"Alright, alright. A year's worth of cat treats. I'll go buy them tomorrow."
At Gin's promise, the little cat finally gave up struggling. He scooped it up and started absentmindedly stroking its fur.
Even cats were negotiating contracts nowadays.
Life wasn't easy, huh.
He casually dropped the cat onto the ground — it twisted midair and landed gracefully on its paws.
"Go entertain yourself. You can stay here for now."
There weren't any summoning beasts at Gin's home — honestly, there wasn't even a ghost wandering around — so letting a cat stay was no big deal.
The little cat licked its paw pads, not even acknowledging if it heard him.
Gin climbed the stairs to the second floor and opened the storage room at home.
"Less than a year left... I need to boost my strength."
He needed to prepare for future battles.
His eyes swept over the shelves filled with scrolls of ninjutsu.
Well, it was normal for a jonin's house to have this many jutsu scrolls.
Some of them were techniques obtained from missions, like the Shadow Clone Technique. The rest were split into two types: ninjutsu collected by the Uchiha Clan and a wide variety of sealing techniques.
But even all this couldn't compare to Konoha's official ninja technique archive.
As for the Uchiha Clan's own jutsu collection, it was much larger than this room, but again, Konoha had copies of everything.
Next to the bookshelves stood a round wooden table with six scrolls neatly laid out in a circular arrangement.
These were techniques Gin had personally spent an enormous amount of time researching and developing.
He hadn't just sat around during his "restricted" period. His eyes glanced quickly over the scroll titles:
Shave, Paper Drawing, Finger Gun, Iron Body, Cat Speech, and Basic Internal Energy.
From the Six Powers (Rokushiki) of the Pirate World, he had managed to replicate four techniques so far. Techniques like Tempest Kick and Moon Walk required chakra to be released externally — something he couldn't yet manage.
Unless his physical stats multiplied tenfold.
To even get this far, he had spent most of his time honing these abilities. Only now did he start teaching Basic Internal Energy to others.
After all, if he taught others too early without being strong himself, he'd basically be throwing away his advantage.
Only when he created even stronger techniques would he start sharing more.
"Man, looking back, it wasn't easy."
To achieve these techniques, he had to explore every possibility step-by-step, build the theoretical framework, and test over and over.
It was almost like writing a massive college thesis.
Thankfully, he eventually succeeded — this was now his ace in the hole.
As for Cat Speech, that came from a long period of observing and recording cat behavior, then recreating it through technique.
Basic Internal Energy was the true cornerstone of everything he built.
"With my current strength, I should be able to easily take down an average chunin. But against a jonin or elite jonin? I'd be dead meat."
That was the theory at least — he hadn't actually fought a chunin yet. But on paper, his power level was solid.
"The problem is, I excel at close combat, while most ninjas prefer medium- to long-range attacks. I need a way to counter long-range ninjutsu."
"Lightfoot techniques."
Gin had made up his mind. In his philosophy, speed equals power.
If he couldn't win, at least he could outrun anyone — especially with something similar to the legendary Lingbo Weibu (Rippled Steps), supercharged with chakra.
If he combined it with Shave for even longer jumps?
He refused to believe anyone could catch or hit him.
He already had some theories, but hadn't pieced everything together yet.
"Use Paper Drawing for sensory detection, Shave for instant movement, and layer it with Five Elements and Eight Trigrams patterns."
In his past life, he'd been coaxed into reading books like the I Ching and studying Bagua patterns during a bout of spiritual obsession.
His memories were blurry, but he could reconstruct the theory with his current deduction system.
He summoned the system's text panel — and, with a thought, blurry memories of the I Ching and Eight Trigrams appeared.
Next, he grabbed ninjutsu scrolls about movement techniques and collected data on the attack ranges of large-scale ninjutsu.
First, he needed to organize all this info, refine the details, complete the theoretical structure, and input it into the system.
"Deduce!"
The system whirred to life.
[Deduction Failed]
Uchiha Gin: (｀⊿´).
"Seriously, are you some undercover college professor trying to force me to write a thesis?!"
"Do I even have to check for plagiarism now, you bastard?!"
This deduction system really made him feel like he was stuck in an endless university course.
"Where did I go wrong?"
Gin started reviewing his "paper"— uh, the compiled theories.
Right then, his pupils shrank to pinpricks before relaxing again, his face lighting up with excitement.
"Kushina... she broke through!!"
...
A little while earlier.
Kushina had just seen Minato off, her upper body leaning against the window, chin resting in her palms, watching the falling rain.
"Why is my little brother so girly and dumb?"
She was lost in her thoughts. Minato always seemed so clueless, stiff, and blushing like a kid.
Thinking of that annoying Uchiha Gin only made her mood worse.
"Neither of you will ever find a girlfriend," Kushina grumbled.
One was girly, the other had a poisonous tongue.
After tidying up the table, she returned to her room.
This house had once belonged to Mito. When the Nine-Tails was sealed inside Kushina, Mito had passed away.
Now it was her home — but it never truly felt like one.
"I'm just an outsider here."
Kushina sat on her bed, sinking her mind into her body.
That was the only place she could find some peace.
Thanks to the internal energy technique she got from Uchiha Gin, whenever she practiced it, she entered a serene state, gathering her scattered emotions.
Following the instructions of Basic Internal Energy, she focused on her lower abdomen — the dantian.
There, chakra had formed a glowing "egg," occupying her entire lower belly. Any chakra generated would immediately be absorbed by the egg.
Even the Nine-Tails' chakra was no exception.
Surprisingly, once the Nine-Tails' chakra entered the egg, she could completely control it.
The originally blue egg had taken on a golden glow.
"Isn't the fox's chakra supposed to be red?"
Kushina was confused. Sometimes she could consciously enter her internal seal space, where she could see the grumpy fox trapped in a grimy sewer.
Now, it was even easier.
Inside the golden egg, an intricate sealing formation dominated the center. Red specks occasionally bubbled up, merging into the gold.
At first, the Nine-Tails' chakra flowed out in big globs. Now, it only trickled out slowly.
Still, even a trickle was enough — her chakra egg had become solid.
According to the Basic Internal Energy manual, the chakra first weaves a seal formation, then forms a transparent light egg, and finally a solid, opaque one — just like hers now.
"Looks like I completed the first stage."
Kushina thought to herself.
The first stage was essentially about stockpiling chakra. Not super difficult — anyone with chakra could eventually complete it.
The second stage, however, was the real challenge.
"Using chakra to seal the entire chakra network inside my body — and the chakra must come from the egg."
But the manual didn't say how much chakra she needed, and Gin hadn't mentioned it either.
"Probably a lot," she guessed, frowning slightly.
She sank her mind deeper into the chakra egg's center.
A dark space.
A giant stone prison surrounded by mountains.
In the darkness, two scarlet eyes opened, glaring at the little girl before shutting again.
Kushina wasn't scared. She confidently approached the giant fox caged behind massive iron bars.
The fox lay sprawled out, seemingly asleep.
She kicked the bars hard — clang clang.
"Hey, big fox, stop pretending. Lend me some chakra!"
The Nine-Tails lazily opened one eye and growled:
"No."
Normally, if it were someone else, he'd have gladly lent chakra — enough to make the jinchūriki lose control and tear apart the seal.
But this tiny brat had learned some crazy technique that devoured his chakra!
What kind of messed-up ninjutsu was that?! He'd never heard of anything like it — it was like a tailed beast's worst nightmare.
Even worse than Mito, who'd occasionally smack him around — this girl was flat-out mugging him.
"You stinky fox, lend it or else!"
When Kushina heard his refusal, her red hair practically stood on end.
The Nine-Tails huffed and turned around, presenting his butt to her.
Which only made her angrier.
"You leave me no choice!"
Three chakra chains sprang from her back, shot past the bars, and wrapped tightly around the Nine-Tails.
The fox howled in pain.
"AWOOOO!!"
Back in her body, Kushina blushed fiercely, staring at the ceiling, muttering:
"Sorry... I didn't mean to... You shouldn't have turned your butt to me."
(Nine-Tails: I hereby declare you the fiercest jinchūriki ever.)
There was no time to dwell on it.
Massive amounts of chakra flooded out of the chakra egg, so much that even the egg couldn't absorb it all.
She calmed herself, focusing with everything she had. Thankfully, the chakra egg's suction power was strong, preventing the Nine-Tails' chakra from leaking outside — otherwise, people would have noticed immediately.
"Use chakra to seal the entire network of chakra channels."
Basic Internal Energy: Second Realm — 'Body Opening Stage' Complete!