Sealing Jutsu Sensei

In the courtyard of the Senju residence, Natsuhiko was still fully engrossed in constructing the runic techniques of the Yin Seal within his body.

The projection of the human meridians on the stone table clearly showed the orderly flow of chakra within Natsuhiko's body and the conversion and connection of the Yin Seal runes. Everything appeared to be progressing smoothly.

Mito, who had been observing everything, couldn't help but feel a deep sense of amazement.

After all, it had only been two months since she handed over the Yin Seal scroll to Natsuhiko.

Even though she had already adjusted her assessment of Natsuhiko multiple times, she was still surprised by how quickly he had officially begun the training of the Yin Seal.

It's important to know that even she, who was called a genius in sealing techniques, took a long time to reach the threshold to begin training in the Yin Seal.

She had learned from Kushina about the infant clone technique.

Thus, she understood that this secret was responsible for Natsuhiko's rapid progress and his ability to handle multiple tasks—school, taverns, and his inventions.

In fact, Natsuhiko was able to start the formal training of the Yin Seal so quickly because of his infant clone technique and the special Yin Seal meridian scroll.

However, Mito didn't reduce her evaluation of him due to these external aids. On the contrary, she appreciated him even more.

After all, even Hashirama, known as the God of Shinobi, couldn't clearly explain where his unreasonable abilities came from, let alone pass them down.

So, although Hashirama was able to suppress the shinobi world during his lifetime, no one inherited his skills after his death, leaving only an unmatched reputation behind.

Even Tobirama, a genius in creating many ninja techniques, had skills that few could master.

Perhaps only someone like Natsuhiko, who came from a humble background with average ninja aptitude, could use his intelligence to pioneer a stable, inheritable path.

This special Yin Seal meridian scroll was a good example.

With Natsuhiko's improvements, it could now visually display even the subtle changes in chakra flow and rune transformation while constructing the Yin Seal technique.

This meant that the previous training method, which relied solely on intuition and personal experience, had become obsolete.

Natsuhiko could now quickly and intuitively grasp his progress using the detailed meridian system chart and even fine-tune the chakra pathways.

In fact, after referencing Mito's own Yin Seal chakra circulation model, Natsuhiko modified the technique to better suit himself.

This was why Natsuhiko was able to start training in the Yin Seal so quickly.

The Yin Seal wasn't just a simple chakra container. During training, the runes formed from the chakra had to spread through the body's meridian system, integrating the entire body's chakra in preparation for various uses after the seal's formation.

Previously, mishandling this process could cause significant damage to the meridians, making training this technique one of the biggest challenges.

Even members of the resilient Uzumaki clan needed to master medical ninjutsu to heal themselves during training before they could officially begin.

However, Natsuhiko was able to significantly reduce this risk by using the meridian scroll.

Combined with his extraordinary chakra control, he dared to begin training the Yin Seal after mastering only basic medical ninjutsu.

Judging by the current situation, Natsuhiko's unconventional approach seemed to have succeeded.

Moreover, this method wasn't just beneficial to him. By following his example, even Kushina and Tsunade could shorten the time needed to master the Yin Seal.

Mito had heard Natsuhiko mention that he wanted to create his technique based on the Yin Seal, akin to the Strength of a Hundred Technique.

Without a doubt, he had already taken an excellent first step.

As Mito watched Natsuhiko with a gratified expression, his training reached a critical moment.

Mysterious patterns began to emerge on his body, extending upwards until they converged into a purple rhombus-shaped mark on his forehead.

Soon, both the patterns and the mark began to fade as if they had never been there.

Seeing this, Mito finally put her last bit of worry to rest, smiling with satisfaction.

It was a success.

After exhaling softly, Natsuhiko slowly opened his eyes.

"You're amazing, Natsuhiko! You succeeded on the first try!"

"Yeah, our real bodies are nowhere near as good. We still haven't learned it yet!"

Several small Kushinas cheered and ran towards Natsuhiko, chattering around him.

Kushina, who had also been joyfully approaching, suddenly froze when she heard her clone's comment.

Indeed, she had been studying the Yin Seal for longer than Natsuhiko, yet she was still stuck at the medical ninjutsu stage.

Although the meridian scroll had lowered the medical ninjutsu proficiency requirement for this technique, it wasn't something you could completely neglect.

Additionally, Kushina, with her vast chakra reserves, wasn't as skilled in chakra control as Natsuhiko, and she needed more training in that area before she could officially start training the Yin Seal.

Although she understood her clone was stating the truth, Kushina still felt indignant and said, "Hmph, just you wait. Once I start training the Yin Seal, I'll catch up to Natsuhiko in no time!"

Mito glanced at the sulking Kushina, then turned her attention back to Natsuhiko, who was surrounded by the little Kushinas, and said, "Actually, Kushina has a point, Natsuhiko."

"Even though you've already formed the Yin Seal technique in your body, you can't afford to be careless."

"After all, the second stage of training is even more difficult than the first."

Natsuhiko, who had freed himself from the little Kushinas, nodded in agreement.

Although the runic patterns on his body had seemed to disappear, they were still operating within him.

The second stage of training involved accumulating chakra. He needed to maintain the operation of the Yin Seal technique while continuously injecting chakra into it.

If the first stage involved creating a container for chakra, the second stage involved filling it up.

In a way, this was similar to the concept of a jinchuriki sealing a tailed beast within their body, except that the Yin Seal stored one's chakra.

Moreover, unlike regular seals, which could function automatically once completed, the Yin Seal required the practitioner to continuously maintain its operation because the container needed to be constantly filled.

This was the difficulty of the second stage—any lapse in concentration would cause the progress to be lost, and they'd have to start over.

Whether eating, sleeping, or fighting, the practitioner needed to split their attention to keep the Yin Seal active.

Only when the container was complete, and the purple rhombus mark was fully formed would the Yin Seal be complete and able to operate independently.

Furthermore, the technique used a "zero-deposit" system; the stored chakra could not be used as long as it wasn't fully formed.

Because of these stringent requirements, the Yin Seal was highly revered but feared among the Uzumaki clan, and only a select few could master it.

Natsuhiko had one major disadvantage in this second stage of training—his perpetually limited chakra reserves.

Due to his infant clone technique and various research activities, he had already been using up all his chakra daily, leaving nothing to spare.

Now, with the Yin Seal demanding even more chakra, his situation had become even more challenging.

Mito couldn't help but ask again, "Natsuhiko, are you sure you still want to allocate so little chakra to the Yin Seal each day?"

"At this rate, it might take you over a decade to fill the Yin Seal."

This was already Mito's optimistic estimate.

The longer the process, the more likely an unexpected incident would occur, causing all progress to be lost.

Additionally, as the seal's chakra level increased, the energy and chakra required to maintain the technique would also rise, continuously raising the difficulty of the training.

However, Natsuhiko had no intention of taking ten years to master the technique.

For now, he was only injecting a small amount of chakra into the seal to keep it running as a form of practice.

So he smiled and said, "It's fine, teacher."

"I already have an idea for how to approach this stage of training."

This time, Mito could roughly guess what Natsuhiko was implying.

Since using his chakra was too slow, he would naturally think of methods to absorb chakra from external sources.

The most direct method would be to add a chakra source within his body—like a tailed beast.

However, unless the tailed beast agreed to cooperate, its interference would prevent the Yin Seal from forming.

Alternatively, there were rare secret techniques in the shinobi world that could absorb chakra from the environment.

Unfortunately, as someone from the Uzumaki clan who married into the Senju clan, neither Mito nor those around her had ever encountered a chakra shortage.

If anyone had less than ten times the normal chakra, they'd be embarrassed even to greet others.

So, Mito did not have access to any such chakra-absorbing secret techniques.

Sighing, Mito lamented, "It's such a pity that our clan has scattered across the world. Otherwise, perhaps someone could have helped you, Natsuhiko..."

(End of Chapter)

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