Inside the study, Tsunade wasted no time getting straight to the point.
"It's about the mass-production problems of a new type of medical ninjutsu scroll. We've hit a wall when it comes to simplifying the sealing formulas, and we need a top-tier Fūinjutsu expert. You were the first person I thought of!"
"A medical scroll? Mass production?"
Kushina blinked.
She immediately caught the key words, and her curiosity was instantly piqued.
"Tsunade-neesan, tell me everything."
So Tsunade quickly explained the medical-scroll project.
As Kushina listened, her eyes grew brighter and brighter.
"Then what are we waiting for? Let's go right now, Tsunade-neesan!"
By the time Tsunade finished, Kushina looked even more eager than she did.
Heaven knew how monotonous her daily life had become.
Although she was safe, staying in the village day after day rarely gave her the feeling that she was truly needed.
Now, hearing about a project that could make such a tremendous difference and save countless comrades' lives in the future, she could no longer sit still.
The two women turned to leave the study.
"Wait, Tsunade-neesan!"
Kushina suddenly remembered something.
"Can I bring one more person? She might be able to help, and it'll also be a valuable learning opportunity."
Tsunade paused.
"Who?"
"Rin."
Kushina smiled.
"That girl is thoughtful, meticulous, and very talented when it comes to chakra control. She's got real potential for medical ninjutsu."
"Minato is an excellent sensei, but medical ninjutsu isn't exactly his specialty. I've always felt like her talent in that area hasn't had the chance to fully develop."
"If she could follow you around during this medical-scroll project, even if she's only helping with small tasks and observing, she'd definitely learn a great deal."
"You're quite considerate of other people."
Tsunade chuckled.
"Alright, bring her along. But let me make one thing clear—how much she learns from me will depend entirely on her own ability."
"No problem!"
The two women stepped out of the study.
Kushina waved toward Rin at the dining table.
"Rin! Come here! You're coming with Tsunade-neesan and me! We have an important mission!"
Rin froze for a moment before quickly standing up.
"Yes, Kushina-nee-san!"
Moments later, Tsunade, Kushina, and Rin hurried off together, leaving behind a noticeably quieter house and three men exchanging confused looks—
Minato, Kakashi, and Obito.
"What are they even up to? Acting all mysterious..."
Obito grumbled under his breath, a little jealous that Rin had been chosen to participate in such an important project.
"Just eat your food, dead last."
Kakashi shot him a glance.
"Who are you calling dead last?!"
"Alright, alright."
Minato smiled and stepped in before the argument could start.
"They must have something important to deal with. Let's keep eating."
Meanwhile, Kushina's departure with Tsunade had naturally been noticed by the ANBU stationed nearby.
They were responsible for monitoring, guarding, and protecting the Nine-Tails Jinchūriki.
The report was quickly relayed to the Hokage's office.
"I understand."
After hearing the ANBU's report and learning that Kushina had gone to Shinichi's private laboratory with Tsunade, the Third Hokage, Sarutobi Hiruzen, merely nodded.
"Continue your protection detail. Do not interfere with them. Report again if anything unusual occurs."
Still, he couldn't help feeling curious.
Have they come up with something extraordinary again?
For a moment, even the Third Hokage found himself filled with anticipation.
Some time later, the dinner gathering at Minato's house came to an end amid a somewhat quieter atmosphere.
Minato politely declined Kakashi and Obito's offers to help clean up.
After the two boys left, he rolled up his sleeves and cleaned the table and kitchen by himself.
Just as he finished putting away the last washed plate and wiped the water from his hands, another knock sounded at the front door.
"Kakashi? Did you forget something?"
Standing outside, Kakashi seemed to be organizing his thoughts.
Then he spoke.
"Minato-sensei, sorry to bother you again. I've run into some new problems with my Lightning Release training and wanted to ask for your guidance. Do you have time right now?"
"Of course."
Minato smiled.
"Let's go to the training ground."
He assumed Kakashi was still struggling with issues related to Chidori.
However, a short while later, beneath the moonlight of Konoha's Fifth Training Ground—
Seeing the countless arcs of lightning flickering around Kakashi's body, Minato's eyes widened.
"This is...?!"
"Nintaijutsu?"
At the same time, back in the laboratory, Tsunade burst through the door with Kushina and Rin in tow.
"I brought the person you need!"
Tsunade nodded toward Shinichi and stepped aside, revealing the red-haired kunoichi behind her.
"This is Uzumaki Kushina, one of the greatest Fūinjutsu experts in the ninja world."
"Kushina, this is Higashino Shinichi. I'm sure you've heard about him plenty of times already."
"Heard about him?"
Kushina laughed.
"Tsunade-neesan, I'm a loyal fan of Number One Chef! I haven't missed a single issue!"
Her gaze immediately locked onto the black-haired boy standing behind the workbench.
Her eyes lit up.
"So you're Shinichi?"
She strode forward enthusiastically.
"You're way more handsome than the photo in the author's profile!"
"I already heard the basic story from Tsunade-neesan."
"Excellent work!"
As she spoke, her attention had already shifted toward the blueprints, scroll samples, and research notes spread across the workbench.
"Now then, we can save the pleasantries for later."
"Let's get straight to work."
"Time is precious."
"Show me every piece of experimental data you have. Failed attempts, material-property analyses, complete reports, and every sealing-formula structure you've tried so far."
"I need to understand the situation as quickly as possible and find the breakthrough point for mass production."
...
Five days later.
Inside the laboratory.
"YES! WE DID IT!!!"
A cry of pure exhilaration exploded through the room, shattering the tense and quiet atmosphere that had dominated the laboratory for days.
Kushina held a newly tested medical scroll high above her head.
Excitement and pride radiated from her face.
Even her red hair seemed to dance with her enthusiasm.
On the workbench before her were more than fifty medical scrolls of identical specifications arranged in neat rows.
Every single one represented a successful seal and stable energy storage.
"That's amazing!"
"We actually did it!"
Beside her, Kurenai, Shizune, and Rin all wore relieved and overjoyed smiles.
The exhaustion from days of intense work vanished beneath an overwhelming sense of accomplishment.
Kushina carefully set the scroll down and turned toward everyone in the laboratory, especially Tsunade and Shinichi.
Her eyes sparkled as she quickly explained: "Look!"
"This finalized medical-storage seal is stable. Chakra circulation efficiency meets the required standards."
"And most importantly—"
"It's simple enough!"
"Any ninja with a basic foundation in Fūinjutsu can master it after a short period of training and quickly produce qualified empty storage scrolls."
"After that, all a medical ninja needs to do is inject and seal a C-rank medical ninjutsu like Healing Technique or a hemostasis technique into the scroll."
"And just like that, you've got a finished medical scroll!"
"We've established the theoretical foundation for mass production!"
After her excitement subsided, however, she let out a sigh.
"Still, it's a shame."
"At the moment, we can only perfectly seal C-rank medical ninjutsu like Healing Technique and hemostasis techniques."
"If only we could create medical scrolls capable of storing higher-level techniques like the Healing Resuscitation Regeneration Technique or even the Mystical Palm Technique..."
"That would allow us to handle far more severe and dangerous injuries."
Hearing that, Shinichi smiled.
"Kushina-senpai, every journey has to be taken one step at a time."
"In such a short period, we've already overcome two major obstacles—the material problem and the basic sealing problem."
"We achieved a breakthrough from zero to one."
"We turned the stable storage of medical ninjutsu from theory into reality."
"That alone is a miracle the ninja world hasn't witnessed in hundreds of years."
Picking up one of the scrolls, he continued: "For the vast majority of battlefield casualties and common mission injuries, reliable access to Healing Technique and hemostasis techniques is already enough to stabilize their condition."
"In many situations, even if they can't fully treat severe wounds, they'll still allow injured comrades to survive long enough to reach proper medical care."
"And that alone will save countless lives."
"As for increasing storage capacity, refining the sealing formulas to accommodate higher-level medical ninjutsu, reducing production costs, and increasing output..."
He smiled at Kushina.
"Those are deeper and far more challenging problems."
"We'll have to rely on Kushina-senpai to continue advancing the field of Fūinjutsu if we want to solve them."
"Absolutely! Completely possible! Leave it to me!"
Kushina nodded vigorously.
Her fists clenched unconsciously, fiery determination blazing in her eyes as she said excitedly, "One day, I will—I absolutely will—develop new sealing formulas capable of reliably storing higher-level medical ninjutsu!"
"I'll make these medical scrolls the strongest safeguard protecting our comrades' lives!"
To her, this feeling was incredibly precious.
The Third Hokage and Konoha's leadership had always told her that, as the Nine-Tails Jinchūriki, she was immensely important to the village.
But that kind of importance often left her feeling strangely empty.
Now, she had finally found something through which she could actively create value—something where she was genuinely needed and could directly benefit countless comrades.
"Although..."
Kushina's brows furrowed again as she looked at Tsunade and Shinichi.
"What about the material supply?"
"After five days of intensive testing and prototype production, there isn't much left of those special trees created by the First Hokage's Wood Release in the Forest of Death."
"If we're really going to mass-produce these, securing a supply chain for the raw materials has to be the top priority."
"That's not something we need to worry about for now."
Tsunade crossed her arms.
"Within the Senju Clan's ancestral grounds, Grandfather left behind an entire forest of special trees that he personally cultivated while practicing and researching Wood Release."
"It's a fairly large forest."
"No one ever thought of using it this way before, but as far as raw materials are concerned, the supply will be more than sufficient for a long time."
"That's great!"
Kushina's eyes lit up.
The weight on her heart immediately lifted, and her bright smile returned.
"Then what are we waiting for?"
"We need to tell the Hokage-sama right away!"
"He has to know what a huge accomplishment we've pulled off while locking ourselves in here!"
"We've done something incredible for the village!"
She could already imagine the Third Hokage's shocked yet gratified expression when he heard the news.
...
Hokage Office
"W-What?!"
"You've developed medical scrolls?!"
"The kind that can be mass-produced?!"
The Third Hokage, Sarutobi Hiruzen, nearly dropped his pipe as he shot to his feet.
From the ANBU reports and the group's activities over the past several days, he had already guessed that Shinichi, Tsunade, and Kushina were working together on a major project.
Most likely something related to medical ninjutsu or Fūinjutsu.
But even so, hearing the words mass-producible medical scrolls exceeded every expectation he had held.
Without the slightest hesitation, the Third Hokage immediately rose from his chair and strode out of his office, heading directly toward Shinichi's laboratory.
As he hurried there, his thoughts rapidly shifted from shock to assessment.
First came the strategic implications.
Even if the scrolls could currently store only C-rank techniques like Healing Technique and hemostasis techniques, the true power lay in one word:
Mass production.
That meant every frontline squad—and potentially every individual shinobi—could eventually carry at least one lifesaving scroll.
Such a development would dramatically improve Konoha's battlefield survival rates and sustained combat capability.
Injured shinobi could receive immediate stabilization.
More wounded soldiers would survive long enough to be evacuated from the battlefield.
More elite personnel could be preserved.
This was not merely a revolution in medical logistics.
It was a strategic weapon capable of directly enhancing Konoha's overall military strength.
In a brutal war of attrition, even a slight increase in survival rates could accumulate into the decisive factor that determined the outcome of the entire conflict.
Then came the economic implications.
A colossal money tree.
Once the technology matured and production stabilized, the value of such convenient and reliable medical scrolls would be immeasurable.
Konoha itself would require huge quantities.
The Land of Fire's Daimyō, regional governments, wealthy merchants, nobles, and even foreign nations and hidden villages that maintained friendly or neutral relations with Konoha would likely line up with enormous sums of money to purchase them.
This could become an entirely new pillar industry for Konoha.
A strategic industry capable of generating a continuous flow of wealth and resources.
Resources that could be reinvested into infrastructure, public welfare, military development, and further cutting-edge research like this.
However, economic returns were a long-term matter requiring careful management.
Right now, Hiruzen's thoughts focused on the most urgent application:
The war.
The more he considered it, the brighter the fire burned within him.
His pace quickened once again.
He almost wished he could fly directly to the laboratory and witness the miracle with his own eyes.
...
Laboratory.
When the Third Hokage appeared at the doorway, the excitement that had only recently settled immediately surged once more.
Kushina was the first to jump up.
Her face practically screamed, Praise me! Praise me!
There was even a trace of smug pride mixed into her brilliant smile.
Tsunade stood with her arms crossed and chin slightly raised.
Shinichi stood nearby, calm and composed as ever.
Shizune, Kurenai, and Rin stood a little farther back, their faces still flushed with the excitement of having participated in a historic achievement.
The Third Hokage's gaze immediately landed on the rows of medical scrolls covering the workbench.
He strode forward.
Without even speaking, he carefully picked one up and began examining it.
They had actually done it.
And the completion level was astonishingly high.
His own mastery of Fūinjutsu was considerable, so it didn't take long for him to understand what he was looking at.
Slowly, he rolled the scroll back up.
Then he raised his head and looked at the young faces before him.
A broad, satisfied smile spread across his face.
"Good!"
"Good!"
"Good!"
"You've done exceptionally well!"
"You've rendered a tremendous service to the village."
"Konoha is proud of all of you."
As he praised them, another, more practical thought flashed through his mind.
Raw materials.
The forest within the Senju ancestral grounds might contain a substantial supply, but it was far from limitless.
After all, he knew better than anyone that the trees created through the First Hokage's Wood Release grew extraordinarily slowly.
And whether transplanted saplings or newly cultivated offspring would retain the same special properties remained completely unknown.
That meant that if medical scrolls were truly produced and consumed on the scale they envisioned, the raw materials used to make Shinichi Paper would eventually face the risk of depletion.
The thought made the Third Hokage frown inwardly.
Could it be...
The idea surfaced in his mind once more.
But Hiruzen quickly dismissed it.
'Let's wait and see. That's a problem for the future.'
For now, celebrating the achievement and planning its implementation were the priorities.
With that in mind, the Third Hokage smiled again and enthusiastically joined the discussion with the group of young people who had created this miracle.
The conversation quickly shifted toward practical matters: how to efficiently train personnel, establish production lines, and create standardized procedures.
Yet while Konoha quietly gave birth to a medical breakthrough capable of reshaping the entire medical landscape of the ninja world, the increasingly turbulent situation across the shinobi world showed no signs of slowing down.
...
May 5th, Year 47 of Konoha.
Explosive news spread throughout the ninja world like a thunderclap.
Claiming that its shinobi had disappeared under suspicious circumstances while carrying out missions within the Land of Lightning—and were likely victims of foul play—Iwagakure issued a formal ultimatum to Kumogakure.
The demand was clear:
Iwa would dispatch a large-scale search force into the Land of Lightning and conduct a thorough, unrestricted investigation to ensure the safety of its shinobi and uncover the truth.
It was the very same excuse Kumogakure had once used to declare war on Konoha.
Now Iwagakure was using it against them.
No one knew what the people of Kumogakure thought when they received that ultimatum.
According to rumors, the hot-tempered Third Raikage flew into a rage upon reading the official document and shattered his sturdy office desk with a single strike.
As a result, later that very night, Iwagakure formally declared war on Kumogakure.
The news sent shockwaves throughout the ninja world.
However, Iwa's forces did not immediately advance into the Land of Lightning itself.
Instead, they launched a fierce invasion of the Land of the Moon, one of the Land of Lightning's subordinate nations.
The intention was obvious.
Iwagakure planned to use the Land of the Moon as a staging ground and forward operating base.
At that point, four of the Five Great Shinobi Villages had officially become participants in the Third Shinobi World War:
Sunagakure.
Kumogakure.
Iwagakure.
And Konoha, which was simultaneously fighting both Suna and Kumo.
Only Kirigakure remained absent.
Separated from the continent by the vast ocean, the Hidden Mist Village had yet to officially enter the war.
But anyone with clear eyes understood the truth.
Kirigakure's participation was only a matter of time.
Along the long southeastern coastline of the Land of Fire, confrontations and friction between Konoha and Kirigakure had become increasingly frequent.
The smell of gunpowder grew stronger by the day.
Clashes fought under the pretext of mission disputes had become commonplace.
Bloodshed between the two sides was no longer news.