After regaining her composure, Yoruichi Shihōin glanced once more at Gosuke Shigure.
"Sensei, aren't you…?"
Earlier, Gosuke Shigure had called them "very brave."
After all, this was Sōkyoku Hill — the official execution ground of the Soul Society — and her teacher, Gosuke Shigure, was a Gotei 13 Captain, one of the very people entrusted with maintaining the order of the Seireitei.
No one could predict whether he would report them.
Naturally, Yoruichi felt a trace of unease.
"Don't worry. I won't report you." Gosuke Shigure's voice was calm, his perceptiveness instantly catching Yoruichi's anxiety.
Seeing her startled expression at his accuracy, Gosuke Shigure continued,
"However, even if I don't report you for carving out a training ground here, if you and the boy beside you don't learn to conceal your Reiatsu, someone will sense you sooner or later."
"Then… what should I do? Is this place unsuitable for private training after all?" Yoruichi's voice carried faint frustration and disappointment.
Gosuke Shigure replied, "Either you learn how to suppress and mask your Reiatsu, or you erect a Kidō barrier around this entire area to block spiritual pressure from leaking out."
Yoruichi nodded slightly. "Kisuke and I have considered erecting a barrier, but… we don't have the capability yet."
Although Urahara Kisuke had self-taught some Kidō, his proficiency was limited to basic Hadō and Bakudō. Crafting large-scale concealment barriers required mastery over advanced Bakudō, knowledge Kisuke had not yet obtained from the Kidō Corps archives.
Of course, that hadn't stopped them from planning ahead — someday, when they had mastered barrier Kidō, they intended to set up a fully shielded training ground.
"I've dabbled in Kidō," Gosuke Shigure said softly. "Who told you I'm only a swordsman? Since I'm your teacher, I'll lend a hand. It's bold to build a hidden base here, but also ingenious. Beneath Sōkyoku Hill, the Reishi density is far higher than the average Seireitei sector. This place is naturally concealed from prying eyes."
He gave a faint smirk. "It would be a waste to abandon it. I'll help you set up a barrier for now. When you grow stronger, you can reinforce or modify it yourselves."
Yoruichi's golden eyes lit with gratitude, and she bowed lightly. "Thank you, Sensei."
Even the usually composed Kisuke dipped his head respectfully. "Thank you, Captain Gosuke."
"It's nothing," Gosuke replied with a small chuckle.
Without delay, he began constructing the barrier.
Kisuke observed every movement carefully — the layering of Bakudō incantations, the intricate Reiryoku flow, the anchor points established in the cavern walls. His gaze was so intent that Gosuke Shigure, noticing it, began explaining his process step by step: how to safely weave spiritual threads, how to leave a controlled gap for entry and exit without compromising concealment.
Before long, the underground chamber Yoruichi and Kisuke had carved out no longer resembled a crude cavern. The newly formed barrier enclosed it in an invisible shell, giving it the feel of a true secret training ground.
Yoruichi, however, cared little for the technical side of Kidō construction. Seeing her teacher appear so unexpectedly, she took this rare opportunity to bring up what had been weighing on her mind.
Once Gosuke Shigure and Kisuke had completed the barrier, Yoruichi stepped forward.
"Sensei… is the theory you taught me really possible?"
"During this past month, Kisuke and I have tried countless times, but not once have we succeeded."
"Oh?" Gosuke Shigure's brow lifted slightly.
He had introduced her to the idea of Shunkō largely to see if she might attempt it earlier than in the original flow of events — but he hadn't expected her to throw herself into it immediately.
At her current stage, she had not yet mastered high-tier Kidō nor reached her eventual pinnacle in Shunpo. Achieving Shunkō at this point was, frankly, impossible.
He sighed inwardly.
In the original timeline, the exact moment Yoruichi perfected Shunkō was never stated, but Sui-Feng had taken years to develop it, already serving as 2nd Division Captain at the time. Even with captain-class strength, it still required long, grueling refinement.
For Yoruichi to master it in a single month was beyond unrealistic.
Still, Gosuke Shigure kept those thoughts to himself.
Instead, upon hearing Kisuke's explanation relayed through Yoruichi, he nodded.
"This boy Kisuke is correct. To achieve Shunkō, you can't rely on another to cast Kidō on you. That approach is flawed from the start."
"Only Kidō you cast yourself can merge seamlessly with your Hakuda. Any Kidō applied externally — no matter how precise the timing — will never fully synchronize with your body's rhythm."
"Yoruichi, you're being far too impatient." His tone sharpened.
"I told you the concept so you could refine it slowly over the years. Instead, you've tried to force its creation in mere weeks. Did you truly believe such an advanced fusion of Hakuda and Kidō could be forged in so short a time?"
"Even creating a single advanced variant of Shunpo can take decades of relentless work. Shunkō is more complex still — it's a complete integration of Kidō into Hakuda combat. Without solid Kidō foundations, it is impossible."
"You must first learn Kidō to a level where you can shape its output as naturally as breathing. Only then, combined with mastery of Hakuda, can you begin attempting Shunkō."
"I… I see…" Yoruichi fell silent, her usual confidence faltering under his blunt assessment.
She had not once considered the full scope of difficulty.
When he had first described Shunkō to her, she had seized on the idea with unshakable determination, already imagining the day she could unveil it before her grandfather — never once pausing to consider that she was attempting to forge a completely new fighting style from scratch.
"Shunkō…" Yoruichi repeated the name softly, still holding onto that ember of stubbornness.
"But… how can I be sure this theory even works? Sensei… is Shunkō truly possible?"