Wind Style: Vacuum Blade.
A B-rank Wind Style ninjutsu. Its effect is to infuse Wind Style chakra into a kunai, forming a sharp sword.
Its characteristics are extremely low consumption, very few ninja who have mastered it, and extremely high learning difficulty.
Although ninjutsu is not strictly classified by rank regarding consumption—placing more importance on how much chakra the ninja inputs—under conditions of equal input, high-ranking ninjutsu will undoubtedly consume relatively more chakra than low-ranking ninjutsu due to their complexity.
But there are exceptions.
Wind Style: Vacuum Blade is this type of ninjutsu. Although it is a B-rank ninjutsu, it is classified as such mostly due to the difficulty of learning it. In terms of sheer consumption, it is lower than most C-rank ninjutsu—
This is determined by the form of the technique.
This technique combines the shape transformation of Wind Style with a strong adhesion effect on ninja tools.
The so-called strong adhesion effect is similar to the state Asuma Sarutobi would demonstrate to Naruto in the future when explaining Wind Style: infusing Wind Style chakra into a chakra blade and throwing it to pierce through a tree. Normally, achieving that effect requires a considerably high level of training in Wind Style nature transformation, and the ninja tool must be made of special chakra metal.
This is why, despite the technique not looking particularly flashy and its power not appearing overwhelmingly strong, it is classified as B-rank.
But for Hyuga Yu, who possessed very little chakra, this was the most suitable ninjutsu.
The three great assets of the Hyūga Clan—
The Byakugan, the Gentle Fist, and the Eight Trigrams.
Their principles are actually interconnected. They all rely on the Byakugan's ability to see the chakra pathway system and the flow of chakra, releasing chakra continuously or in large quantities from the tenketsu (chakra points) to form the nintaijutsu unique to the Hyūga Clan—the unreplicable Gentle Fist style.
The prerequisite for achieving this is based on the Hyūga clansmen having a chakra volume slightly higher than that of an ordinary ninja. (Example: Adult Kakashi has a Stamina stat of 6, while Neji has 7.)
However,
For Hyuga Yu, just maintaining the consumption of the Byakugan during battle was already quite difficult. It was impossible to allocate his remaining chakra to the continuous Gentle Fist and Eight Trigrams, which required large amounts of chakra.
During last year's Chūnin Exams, it was precisely because he forcibly used the Gentle Fist Art: Eight Trigrams Thirty-Two Palms and crashed halfway through that he suffered a regrettable defeat.
However,
His thirteen years of buried study were not useless.
Hyuga Yu had planned his own growth path a long time ago.
The scarcity of his chakra determined that he could only follow the route of a concise and efficient ninja. His battles often had to end in an instant or within a very short period.
Therefore, he shifted his personal focus to Taijutsu, Ninja Tools, and Medical Ninjutsu, pairing them with the Byakugan to construct a combat system that belonged solely to him.
And now, what was missing to complete the final link of this combat system—
Was precisely this Wind Style ninjutsu: Vacuum Blade!
Hyuga Yu did not originally intend to acquire this ninjutsu in this manner. Instead, he had planned to create a slightly weaker C-rank version himself after deepening his training in Wind Style nature and shape transformation.
After all, the price of obtaining it was somewhat too... heavy.
But plans can never keep up with changes.
Things having reached this point, in order to protect his fiancée, Hyuga Natsu, and to face the battlefield he was about to step onto, Hyuga Yu had no choice but to take this step ahead of schedule.
Yes,
Wind Style is a rare affinity among the ninja population.
And within this extremely small group of ninja, as far as Hyuga Yu knew, there was only one person in the entire Hidden Leaf Village who had mastered the ninjutsu Wind Style: Vacuum Blade—
Danzo Shimura.
Thinking for a moment and clearing his head, Hyuga Yu walked out of the Hokage Residence after posting his mission. He identified his bearings and then ran non-stop toward the Konoha Training Grounds.
If one were to unfold Konoha like a fan,
The Konoha Training Grounds were located in the fifth ring of this massive semicircle, adjacent to the perimeter walls and forest surrounding the village.
The supporting ninja tool shops, blacksmiths, and hardware wholesale markets were all located in this area.
It would take some time for the intelligence regarding the S-rank mission Hyuga Yu had posted to ferment and be passed into the hands of various factions.
(PS: It does not essentially reach the level of S-rank; normally it would be listed as an A-rank mission, but since this is a special period, it has been exceptionally listed as S-rank for various reasons.)
Taking advantage of this time, Hyuga Yu arrived in this area to pick up a "secret weapon" he had been preparing for a long time.
At this time,
The streets outside the Konoha Training Grounds were quite lively, filled everywhere with ninja buying tools or repairing equipment.
Hyuga Yu moved through the crowd, lifted the door curtain, and walked into a large ninja tool shop.
The young apprentice responsible for running errands and entertaining guests inside the shop immediately perked up upon observing Hyuga Yu's white eyes. He welcomed him eagerly,
"Welcome! Guest, how may I help you?"
Hyuga Yu glanced at the other party. Seeing the boy wearing a sky-pointing ponytail and round-framed glasses—clearly a fresh face he hadn't seen before—he said:
"I am here to pick up a custom-made ninja tool."
The apprentice immediately trotted to the counter, found the scroll recording custom tool orders, and flipped through several volumes. He couldn't find the surname "Hyuga" anywhere. He looked up somewhat consistently, his small face blushing as he asked:
"Guest, may I ask when you placed the order?"
"Not that book."
Hyuga Yu shook his head and pointed to a scroll pressed at the very bottom of the counter.
"Look there. Eight years ago, a ninja academy student named Hyuga Yu ordered a ninja tool at this shop."
"Eight years ago?" Hearing this, the apprentice was stunned.
Eight years ago, he hadn't even been born yet. And this Hyūga youth before him was probably only six or seven years old back then, right?
What kind of ninja tool takes eight whole years to forge?
And how much effect could a tool forged for a six or seven-year-old child eight years ago still have now?
"Please wait a moment!" Realizing this was a major matter, the apprentice didn't dare to neglect it and hurriedly began to search.
Just then, a rough voice came from the backyard blacksmith workshop.
"Shōseki—"
"What are you doing dilly-dallying? Where is the ore I asked you to get?!"
"Yes!" The apprentice called Shōseki looked up immediately upon hearing the voice.
"Teacher Iō, I'm coming right now!"
"Too slow! Too slow! Also, haven't you eaten? Give me a bit more spirit! How can such a weak voice forge powerful ninja tools?!"
As the voice rang out, a black-haired old man with a Mediterranean-style balding head poked his head out from behind the curtain of the inner room.
Upon seeing Hyuga Yu standing in the shop, Iō blinked. He felt like he had seen this youth somewhere before, but the image didn't seem to match up perfectly.
"Eh, this young brother looks so familiar..."
Seeing him, Hyuga Yu immediately smiled faintly and greeted him.
"Master Iō, it has been a long time."
Iō.
This man was Konoha's premier ninja tool artisan. Eight years ago, Hyuga Yu had spent one hundred thousand ryō to commission him to forge a unique ninja tool.
"Oh, oh! I remember now. You're that kid from the Hyūga family. I watched your matches during the Chūnin Exams last year. Your ninja tool techniques were brilliant... it's just a pity..."
Iō finally recognized Hyuga Yu and showed a look of realization. But quickly thinking of something, he hurriedly shut his mouth and revealed an embarrassed expression.
"Sorry."
"It's nothing."
Hyuga Yu shook his head indifferently. He had only awakened his Byakugan the year before last, and his mastery of Medical Ninjutsu and Gentle Fist acupoint striking was only at a beginner level.
Chūnin aren't as common as cabbage; to be able to advance to the final tournament stage under those circumstances was already considered dumb luck.
However, things were different now.
Thinking of this, Hyuga Yu looked directly at Iō before him and asked straight away:
"Master Iō, how is the crafting of that ninja tool I ordered coming along?"
Looking at the youth in front of him, Iō immediately remembered the "special ninja tool" commissioned eight years ago. His spirit rose involuntarily, and he laughed proudly:
"That tool has been completed!"
"Last year it was still undergoing the final process, so it couldn't be put to use. I am truly sorry about that!"
Saying so, he beckoned to Hyuga Yu, signaling for him to follow him to the backyard.
"Follow me. It definitely won't disappoint you!"