What Is a Technique?

In front of the Records Office.

A very young ninja walked over. Katsuki recognized him as one of Teacher Sakumo's subordinates. His strength and talent were both excellent, and he was already among the elite of the chunin.

"Katsuki, Lord Sakumo wants to see you."

"Mm, all right. I'll go right away."

After a brief daze, Katsuki did not dare delay. He hurriedly agreed. Sakumo would not call someone over just to make idle conversation. Every time he summoned Katsuki, it was either to teach him something or inspect his recent training progress.

He turned and called out to his two teammates.

"Otoha, Tenzan, you two go back first. I'll be back soon."

"Y-you brat, get lost already. Stop showing off in front of me." Otoha rolled his eyes and waved him away irritably, as though shooing flies.

"Go on, or you'll make us die of jealousy..."

Tenzan shook his head with a bitter smile.

Inside the main camp was a small training ground that had been cleared out.

"Attack me."

Sakumo stood in the middle of the training ground and crooked a finger at Katsuki.

Katsuki crouched low, his right hand gripping a short blade. He slowly inhaled and exhaled, controlling his body as Sakumo had taught him. The muscles in his calves bulged, then exploded with force as he shot forward like a crossbow bolt, charging ahead.

His figure flickered as he crossed more than ten meters in an instant. His short blade flashed coldly as it slashed diagonally toward Sakumo's waist and ribs.

"Too slow!"

Sakumo raised an eyebrow and swept his left hand forward. His slightly pale palm instantly turned iron-gray. With a clang, he blocked the short blade barehanded, producing the sound of metal striking metal. It felt as though the blade had struck not a human body, but a solid slab of granite.

The moment he glimpsed that discolored palm, Katsuki sensed trouble. He immediately withdrew his strength. As soon as he lightly touched Sakumo's palm, he bent low and rolled away along the ground before Sakumo could attack. The short blade in his hand swung toward Sakumo's ankle.

Compared to Sakumo's tall frame, he was far too short. Unless he jumped, he simply could not reach vital areas such as the head or neck. But being small had its advantages too. It made it easier to attack low, aiming for ankles and knee joints. The killing power was no less formidable.

As for rolling around on the ground looking undignified... Katsuki did not dare care about such things. A battle was not a performance.

"Clever little brat."

Sakumo shook his head. Force burst from beneath his feet, and he leaped into the air in an instant. The short blade brushed past the soles of his shoes without touching even a hair. Sakumo then twisted sideways in midair and kicked out, striking Katsuki squarely on the backside. Katsuki immediately rolled away like a ball.

Screech!

The short blade stabbed into the sand. Katsuki halted his rolling momentum, flipped himself up, pulled out the blade, and charged again.

He failed again and again, but Katsuki was not discouraged. It would be strange if he could injure Sakumo after only a few moves. This was not their first sparring session. Every time, Katsuki was beaten black and blue, in a truly miserable state.

However, Sakumo had commandeered this small training ground using his authority as commander. Other than master and disciple, there was no one else there. As long as they did not tear the training ground apart, it would be difficult for anyone outside to know what happened within.

Through repeated beatings and Sakumo's careful guidance, Katsuki gradually corrected his own flaws and learned how to cut open a person's neck, heart, or lungs while expending the least possible strength.

"You can stop now."

Sakumo suddenly reached out, grabbed Katsuki as he charged over, and lifted him up as easily as a chick.

"Your progress is very good. Honestly, it has exceeded my initial expectations." Sakumo set the now-quiet Katsuki back on the ground. That gentle smile returned to his face, making Katsuki's nose sting. Heaven knew that ever since becoming his disciple, Sakumo had always kept a stern face around him.

"Your physical qualities are excellent. Or rather, the Uzumaki Clan is truly astonishing. They're simply... freakish."

Watching the bruises and swelling on Katsuki's face slowly fade, Sakumo could not help but utter those two words. He did not know that even the Uzumaki Clan could hardly achieve such a degree of recovery. This was the powerful vitality and restorative ability Katsuki had gained by developing the Human-Human Fruit.

"My original plan was to have you train Taijutsu and improve your physical qualities as much as possible, then teach you ninjutsu in another year. But now, it seems there is no need to wait that long."

Sakumo spoke with a sigh.

Katsuki's spirits immediately rose at those words. At last, he could learn ninjutsu. As for Sakumo's comments, he treated them as nothing more than passing wind.

"To make sure, come here." Sakumo took a square sheet of white paper from his pocket and handed it over. It was chakra test paper.

Holding the small test paper between two fingers, Katsuki carefully poured chakra into it. In an instant, the paper crumpled. Once it had shriveled into a wrinkled ball, it began to crumble and scatter bit by bit like weathered rock.

"Mm, lightning and earth. Very good, very good!" Sakumo nodded, his face full of praise.

"Katsuki, let me ask you a question. What is chakra?" After pondering for a moment, Sakumo did not begin teaching Katsuki ninjutsu. Instead, he asked a question.

Katsuki froze, nearly blurting out, "The power contained within the Divine Tree's fruit." Fortunately, his mind worked quickly enough for him to catch himself. After a brief pause, he carefully answered as the clan elders had taught him in his childhood, "Chakra is the source of power refined by combining physical energy extracted from the cells with spiritual energy formed through training."

"That is correct. Then let me ask another question. What is ninjutsu?" Sakumo pressed.

This time, Katsuki's head began to ache. Was this a test? He could not help racking his brains over how to answer.

Yet when he truly considered the question, he was stunned. What exactly was ninjutsu? Flashy tricks? A tool for killing? He had never considered such a question before. He remained silent for quite a while, and Sakumo was in no hurry. He had a Shadow Clone outside handling matters anyway, so he had plenty of time.

After a long while, Katsuki slowly said, "Ninjutsu is a method of transforming chakra into energy with other properties, then controlling that energy."

"...Very good. In truth, not only ninjutsu—genjutsu, Taijutsu, all of these are methods of transforming chakra into other, more tangible energy with greater destructive or deceptive properties, then guiding and controlling it. Put simply, they are ways of using chakra." Sakumo lightly stamped his foot, and a mound of earth rose from the ground. He sat directly on it.

"The human body was originally incapable of directly controlling energies such as water and fire. And relying solely on physical strength, aside from those with extraordinary natural gifts, humans could not compare to beasts. But with chakra, people could accomplish all kinds of incredible things through ninjutsu, genjutsu, Taijutsu, Secret Techniques, Kekkei Genkai, and the like."