Secret Weapon

Wind Release: Vacuum Blade.

A B-rank Wind Release Ninjutsu. It let the user infuse a kunai with Wind Release Chakra, forming a sharp blade.

Its key advantage was its extremely low chakra consumption. Very few ninja had mastered it, and it was exceptionally difficult to learn.

Although a jutsu's rank wasn't tied to its chakra cost, what mattered more was how much chakra the ninja put into it,

under the same conditions, higher-ranked jutsu generally consumed more chakra than lower-ranked ones because of their greater complexity.

But there were exceptions.

Wind Release: Vacuum Blade was one such jutsu. Though it was B-rank, it was classified as such more because of how difficult it was to learn. In terms of chakra consumption alone, it cost less than most C-rank jutsu—

because that was determined by the way the jutsu worked.

The jutsu combined Wind Release's shape transformation with a powerful ability to adhere to ninja tools.

This powerful adhesion was similar to the effect Naruto would later learn about from Sarutobi Asuma, when Asuma infused a Chakra Blade with Wind Release Chakra and threw it through a tree. Normally, achieving that effect required an exceptionally advanced mastery of Wind Release's nature transformation, along with a tool made of special Chakra Metal.

That was why, despite not looking flashy or being particularly powerful, the jutsu was classified as B-rank.

But for Hyuga Yu, whose chakra reserves were meager, it was the perfect jutsu.

The Hyuga Clan's three signature arts—

the Byakugan, Gentle Fist, and Eight Trigrams Palms—

were all based on the same principle. They relied on the Byakugan's ability to see the Meridians and the flow of chakra, then released chakra continuously or in large quantities through the body's chakra points to create the Hyuga Clan's unique, inimitable Nintaijutsu: Gentle Fist Style.

The prerequisite for this was that Hyuga Clan members had slightly more chakra than ordinary ninja. (For example, adult Kakashi had a chakra rating of 6, while Neji had a 7.)

However,

Hyuga Yu already struggled to maintain the Byakugan during battle. He couldn't possibly spare enough chakra for the continuous Gentle Fist attacks and Eight Trigrams Palms, both of which required large amounts.

During last year's Chunin Ninja Exams, he had forced himself to use Gentle Fist Style: Eight Trigrams Thirty-Two Palms, only to crash halfway through and suffer a crushing defeat.

Still,

thirteen years of hard work hadn't been for nothing.

Hyuga Yu had planned out his path to growth long ago.

His lack of chakra meant he could only follow a compact, specialized path as a ninja. His battles usually ended in an instant or within a very short time,

so he had shifted his focus to Taijutsu, ninja tools, and Medical Ninjutsu, combining them with the Byakugan to build a combat system of his own.

And now, the final piece missing from that system

was this Wind Release jutsu: Vacuum Blade!

At first, Hyuga Yu hadn't planned to obtain the jutsu this way. He had intended to keep training in Wind Release's nature and shape transformations until he could create a weaker C-rank jutsu of his own.

After all, the price of obtaining it was rather... steep.

But plans couldn't keep up with change.

Now that things had come to this, Hyuga Yu had no choice but to take this step early, both to protect his fiancée, Hyuga Natsu, and to prepare for the battlefield he was about to enter.

That was right.

Wind Release was a rare affinity among ninja.

And among that already tiny group, as far as Hyuga Yu knew, there was only one person in all of Konoha who had mastered Wind Release: Vacuum Blade—

Shimura Danzō.

After thinking it over and sorting out the broad strokes, Hyuga Yu left the Hokage Building, where he had just posted the mission. He got his bearings, then hurried toward the Konoha Training Ground once more.

If Konoha were laid out like a fan,

the Konoha Training Ground would be in the fifth ring of that vast semicircle, near the wall and forest surrounding the village.

The nearby Ninja Tool Shop, Blacksmith Shop, and Hardware and Sundries Market were all located in this area.

It would take some time for news of the S-Rank Mission Hyuga Yu had posted to spread and reach the various factions,

(PS: It didn't actually meet the requirements for S-rank and would normally be classified as an A-rank mission. But this was an extraordinary time, and for various reasons, it would be exceptionally classified as S-rank.)

Taking advantage of the delay, Hyuga Yu came to this area to pick up a "secret weapon" he had been preparing for a long time.

At that moment,

the streets outside the Konoha Training Ground were bustling, filled with ninja buying tools and getting their equipment repaired.

Hyuga Yu wove through the crowd, lifted the curtain, and entered a large Ninja Tool Shop.

The Artisan Servant responsible for running errands and greeting customers immediately perked up when he noticed Hyuga Yu's Byakugan and hurried over to welcome him.

"Welcome! How can I help you, sir?"

Hyuga Yu glanced at him. The boy had his hair tied in a topknot and wore round glasses. He clearly didn't recognize him, so Hyuga Yu said,

"I'm here to pick up a ninja tool I had commissioned."

The servant immediately trotted over to the counter and searched through the scrolls containing custom orders. After checking several, he still couldn't find the surname "Hyuga." He looked up sheepishly, his cheeks red.

"Sir, when did you place the order?"

"Not that one."

Hyuga Yu shook his head and pointed to a scroll at the very bottom of the pile behind the counter.

"Look for an order placed eight years ago by a ninja academy student named Hyuga Yu."

"Eight years ago?" The servant froze.

He hadn't even been born eight years ago, and the Hyuga boy in front of him was probably only six or seven back then.

What kind of ninja tool took eight whole years to make?

And how much use could a tool commissioned for a six- or seven-year-old eight years ago possibly be now?

"Please wait!" Realizing this was important, the servant hurriedly started searching.

Just then, a gruff voice came from the back courtyard of the Blacksmith Shop.

"Saltpeter—"

"What are you dawdling around for? Where's the ore I told you to get?!"

"Yes!" The servant called Saltpeter immediately looked up.

"Sulfur-sensei, I'm coming!"

"Too slow! Too slow! And what, haven't you eaten? Put some more force into it! How are you supposed to forge powerful ninja tools with a feeble voice like that?!"

As the voice rang out, an old man with a bald crown and black hair poked his head out from behind the curtain leading to the back room.

When he saw Hyuga Yu standing in the shop, Sulfur blinked. The boy seemed familiar, but he couldn't quite place him.

"Huh, this young man looks familiar..."

Hyuga Yu saw him and smiled faintly, greeting him.

"Master Sulfur, it's been a long time."

Sulfur was one of Konoha's foremost ninja tool artisans. Eight years ago, Hyuga Yu had paid him a hundred thousand ryo to craft a unique ninja tool.

"Oh, right, I remember now! You're from the Hyuga Clan. I watched your match at last year's Chunin Ninja Exams. Your skill with ninja tools was impressive... though it was a shame..."

Sulfur finally recognized Hyuga Yu and looked enlightened. Then he seemed to realize what he'd said, quickly clamped his mouth shut, and looked embarrassed.

"Sorry."

"It's fine."

Hyuga Yu waved it off. He had only awakened his Byakugan the year before last, and his grasp of Medical Ninjutsu and the Gentle Fist's chakra-point strikes had only just reached the beginner level.

Chunin weren't exactly common. Given his circumstances, making it to the final tournament back then had already been a stroke of luck.

But things were different now.

With that thought, Hyuga Yu looked straight at Sulfur and asked,

"Master Sulfur, how's the ninja tool I commissioned coming along?"

Looking at the boy, Sulfur immediately remembered the "special ninja tool" he had been commissioned to forge eight years ago. His spirits lifted, and he smiled proudly.

"It's finished!"

"We were still working on the final step last year, so you couldn't use it then. I'm sorry!"

As he spoke, he beckoned Hyuga Yu toward the back courtyard.

"Come with me. I promise it won't disappoint!"