Wind Release: Vacuum Blade.
This is a B-rank Wind Release ninjutsu. Its effect is to channel Wind Release chakra into a kunai, forming a sharp, invisible blade along its edge.
Its defining traits are extremely low chakra consumption, a very small number of practitioners, and exceptionally high learning difficulty.
Although a ninjutsu's rank is not strictly determined by chakra consumption, and instead depends on how much chakra the user invests, higher-rank techniques are undeniably more demanding than lower-rank ones when infused with the same amount of chakra. This is due to their greater structural complexity.
There are, however, exceptions.
Wind Release: Vacuum Blade is one of them.
Despite being classified as B-rank, this ranking is based primarily on its difficulty to master. In terms of chakra consumption alone, it is lower than most C-rank ninjutsu.
This is determined by how the technique manifests.
The jutsu combines Wind Release shape transformation with a powerful adhesion effect applied directly to ninja tools. This adhesion resembles the state achieved when Asuma Sarutobi, in the future, demonstrated Wind Release to Naruto by channeling wind chakra onto his blades and using them to pierce solid objects.
Under normal circumstances, achieving such an effect requires an extremely high level of Wind Release nature transformation, as well as specialized chakra-conductive metal.
This is why a technique that appears neither flashy nor overwhelmingly destructive is still classified as B-rank.
For Hyuga Yuu, who possessed very limited chakra reserves, this jutsu was perfectly suited to him.
The Hyuga Clan's three core techniques, the Byakugan, Gentle Fist, and Eight Trigrams Palms, all shared a fundamental principle. They relied on the Byakugan's ability to perceive the chakra pathway system, enabling either continuous or large-scale chakra release from the chakra points to form the clan's unique taijutsu style.
The prerequisite for this combat style was slightly above-average chakra reserves. For example, an adult Kakashi had a stamina rating of six, while Neji had seven.
For Hyuga Yuu, simply maintaining the Byakugan during combat already consumed a significant portion of his chakra. Allocating additional chakra for continuous Gentle Fist strikes or Eight Trigrams Palms was unrealistic.
During last year's Chunin Exams, he had been forced to concede defeat precisely because he pushed himself to use Gentle Fist Art: Eight Trigrams Thirty-Two Palms, exhausting his chakra midway through the technique.
Still, thirteen years of accumulated knowledge had not gone to waste.
Hyuga Yuu had planned his development path long ago.
His limited chakra reserves meant that he could only pursue a combat style that was short, decisive, and lethal. His battles had to end quickly.
Because of this, he focused on taijutsu, ninja tools, and Medical Ninjutsu, combining them with the Byakugan to build a personal combat system tailored specifically to his limitations.
Now, the final missing piece to complete that system was this Wind Release ninjutsu: Vacuum Blade.
Originally, Hyuga Yuu had not intended to obtain this technique in such a manner.
His initial plan was to continue refining his Wind Release nature and shape transformation, then develop a weaker C-rank variant on his own. The price of acquiring Vacuum Blade directly was simply too high.
But plans changed.
Given the current situation, and with the need to protect his fiancée, Hyuga Natsu, while stepping onto a battlefield, Hyuga Yuu had no choice but to act ahead of schedule.
Wind Release was a rare chakra nature.
Among the already small group of Wind Release users, as far as Hyuga Yuu knew, there was only one person in all of Konoha who had mastered Wind Release: Vacuum Blade.
That person was Shimura Danzō.
#
After organizing his thoughts, Hyuga Yuu left the Hokage Tower.
He quickly adjusted his direction and headed straight toward the Konoha Training Grounds.
If Konoha Village were arranged like a fan, the training grounds would lie in the fifth outer ring, close to the village walls and the surrounding forest. Most ninja tool shops, blacksmiths, and equipment suppliers were concentrated in this area.
It would take time for information regarding the S-rank mission Hyuga Yuu had posted to circulate and reach the various factions.
Strictly speaking, it was not truly S-rank. Under normal circumstances, it would have been classified as A-rank, but due to the wartime situation, it had been temporarily elevated.
Taking advantage of this window, Hyuga Yuu came here to retrieve a weapon he had prepared long ago.
The street outside the training grounds was lively, filled with ninja purchasing tools and repairing equipment.
Hyuga Yuu moved through the crowd, lifted the shop curtain, and entered a large ninja tool store.
The young apprentice inside immediately noticed his Byakugan and straightened up.
"Welcome. How may I help you, sir?"
"I'm here to collect a custom-made ninja tool," Hyuga Yuu replied.
The apprentice hurried to the counter, pulled out the registry scroll for custom orders, and flipped through several pages. He frowned slightly when he failed to find the Hyuga surname.
"Sir, when was the order placed?"
"Not that one," Hyuga Yuu said calmly, pointing to a scroll pressed beneath the counter. "Look for an order placed eight years ago by a Ninja Academy student named Hyuga Yuu."
"Eight years ago?"
The apprentice froze.
He had not even been born back then. The Hyuga standing before him must have been only six or seven years old at the time.
What kind of ninja tool took eight full years to complete?
Before he could dwell on it, a gruff voice shouted from the back.
"Shōseki."
"What are you standing around for? Where are the ores I told you to fetch?"
"Yes, Master Iō. I'm coming!"
The apprentice snapped to attention.
"Too slow. And speak up. How do you expect to forge proper ninja tools with a voice like that?"
As the scolding continued, a black-haired old man with a receding hairline pushed aside the inner curtain and stepped into the shop.
He paused when he saw Hyuga Yuu.
"This young man looks familiar," Iō muttered.
Hyuga Yuu smiled faintly. "Master Iō. It's been a long time."
Iō was Konoha's foremost ninja tool craftsman.
Eight years ago, Hyuga Yuu had paid him one hundred thousand ryo to forge a special weapon.
"Oh, right. You're that Hyuga boy," Iō said after a moment. "I watched your match in last year's Chunin Exams. Your ninja tool handling was impressive."
He stopped mid-sentence, looking slightly awkward.
"My apologies."
"It's fine," Hyuga Yuu replied.
Back then, he had only just awakened the Byakugan. His Medical Ninjutsu and Gentle Fist control were still rudimentary. Reaching the final round had already been a matter of luck.
Now, things were different.
"Master Iō," Hyuga Yuu asked directly, "how is the ninja tool I commissioned?"
Iō's eyes lit up. "It's finished."
"Last year, it was still undergoing the final process. I regret that you couldn't use it then."
He waved his hand enthusiastically. "Come. I'll show you."
"Trust me. It won't disappoint."