Kato Dan's Secret Ninjutsu
Although Uchiha Mingjing had learned the basics of hemostasis, he was still just a beginner. At best, he could perform simple wound treatments after battle.
Trying to use it during combat was a different matter—stopping the bleeding from even a shallow wound could take several minutes. That level of delay simply wasn't practical in a real fight.
"Not bad."
After Tsunade finished instructing Nami Aburame and Ryo Inuzuka, she gave a small nod of approval.
"But this alone isn't enough to prove you have the potential to become a qualified medical ninja. At the very least, you'll need to pass the next test—reviving a dead fish. That will show whether your chakra control is precise enough to learn advanced medical ninjutsu. But we'll deal with that later."
Tsunade turned to glance at Kato Dan, who was currently grilling fish nearby.
"For now, the priority is finishing off these pheasants and rabbits and getting some food in our stomachs."
Soon after, the game was cleaned and prepared by Mingjing and the others. They drained the blood, applied a mixture of herbal juice and honey brought by Tsunade, then skewered the meat with branches sharpened using kunai and placed them on a rack Kato Dan had built over the fire.
Ordinarily, such a roasting process would take a while. However, as a seasoned shinobi well-versed in the Fire Release nature transformation, Kato Dan had no difficulty controlling the temperature with precision. With subtle adjustments to his chakra, he managed to roast everything perfectly in just over twenty minutes.
Judging by his fluid, practiced movements, it was likely he'd cooked this way often while on missions with Tsunade.
After all, with the power they wielded, most missions posed little threat. The remaining time was often spent training—or simply enjoying the journey.
The roasted pheasant gleamed with a golden sheen. When torn open, the inside revealed juicy, tender white meat. The outer layer was crisp, while the inside remained moist and full of flavor—crackling slightly as oil sizzled off the surface.
The three Genin gathered around the fire, chewing happily on the meat and chatting casually about their hopes and future paths as shinobi.
Tsunade sat nearby, her hands resting on her knees, conversing quietly with Kato Dan by the riverside.
"If you're done eating, come over here."
Kato Dan's voice cut through the warm crackling of the fire. The three students turned to him as he gestured them closer.
Looking at the trio, who now bore the quiet edge of battle-tested warriors, Kato Dan offered a rare, faint smile.
"I've been your instructor for a while now, but aside from treating you to the occasional barbecue, I haven't given you anything of real value. So, I'd like to take this opportunity to pass on a special secret technique—something I created myself."
He stretched lazily and pulled a small ninjutsu scroll from the pouch at his waist.
Mingjing's eyes widened slightly.
Could it be… that technique?
But he quickly dismissed the thought. Surely Dan wouldn't pass down such a dangerous jutsu to mere Genin. More likely, it was some auxiliary technique.
As expected, Kato Dan unrolled the scroll and explained:
"There's a forbidden jutsu in the village called the Spirit Transformation Technique (Shintenshin no Jutsu)—a technique passed down through the Kato clan. It allows the user's soul to separate from their body and possess others. But it's extremely dangerous, and during training, death is a real possibility. So I won't be teaching that."
"What I am going to teach you," he continued, "is a secret support technique developed from the same principles—a safer method to enhance your mental energy. It's called the Spiritual Activation Technique."
"This technique is designed to develop a shinobi's mental energy to its fullest potential. The level of improvement depends on your innate mental strength. I was born with high mental capacity, which is how I eventually managed to master the Spirit Transformation Technique itself—after first using this method to prepare myself."
Dan looked each of them in the eye, his tone growing more serious.
"When your mental energy reaches a certain threshold, it feeds back into your chakra control. That's especially critical for those aiming to learn advanced medical ninjutsu."
At that point, Tsunade raised a hand casually.
"I wouldn't have been able to perform techniques like Chakra Scalpel or Mitotic Regeneration without precise chakra control—and this mental cultivation technique was the first step."
Dan nodded.
"This kind of improvement also benefits sensory-type ninjas. Ryo, Nami—if your mental energy increases, your sensory range and accuracy will improve significantly. That could elevate your detection and response capabilities by an entire tier."
Then his gaze shifted to Uchiha Mingjing.
"And as for you—"
"Sensei," Mingjing interrupted impatiently. "Can we skip the suspense? Will this technique have any effect on the Sharingan?"
He wasn't just curious—he was concerned. It was well-documented that the evolution of the Sharingan placed intense strain on the user's mental state. Some even lost their way entirely. If this technique interfered with that, it could be disastrous.
Dan paused for a moment, then answered honestly.
"I'm not sure. But based on the principles behind it, there shouldn't be any conflict with bloodline traits. In fact, I believe this technique synergizes well with most chakra-based abilities."
He looked at Mingjing firmly.
"You and I share something uncommon—natural, powerful mental energy. That means you have a high probability of reaching the peak of this technique, just as I did."
With that, Dan raised a single senbon between his fingers.
"Once your spiritual energy is sufficiently developed, you can use Yin Release to interact with the physical world—without any medium."
He released the senbon, and it floated briefly in the air before gently drifting to the ground.
"This is similar to the Nara clan's Shadow Possession techniques, which also fall under Yin Release. But while they require a medium—the shadow—I can use pure spiritual power."
"If you ever reach this level," he continued, "then you'll be ready to attempt the Spirit Transformation Technique itself."
He turned to Ryo and Nami.
"You two as well."
Though both had strong potential, Dan reminded them of the inherent danger.
"Many have tried and failed to master the Spirit Transformation Technique. Without sufficient mental energy, your soul won't return once it leaves your body."
This was the standard Kato Dan had set for himself—and now, it was the standard he set for his students.
He looked at Mingjing once more.
"With the Spiritual Activation Technique, I believe you—like me—can reach that level. But tread carefully. This is a path of power that demands absolute mental discipline."