Kisaragi Akira was already well aware of "Ikkotsu," and the memory of it was vivid in his mind.
A single strike from it could crush mountains and split rivers; even a Hollow of Espada caliber couldn't withstand it. He remembered it all too clearly. When Yamamoto's Zanpakutō, Ruribana, had been sealed, a single punch nearly obliterated Wandewyse. At full power, Ikkotsu would turn him to mush in an instant. Sure, Wandewyse wasn't the sharpest tool in the shed and had lost his speech, but what he gained in return was sheer strength—an absolute Espada-level force. And yet, Yamamoto had erased him in a blink.
That alone spoke volumes of Yamamoto's strength. Just as he had said himself: even after a thousand years, he remained the captain of the Gotei Thirteen because no Shinigami stronger than him had appeared.
Though much of the potency of Ikkotsu came from its wielder, it still reflected the technique's overwhelming power. Kisaragi Akira had been anticipating this lesson for quite some time.
"How do I learn it?"
Excited, he stripped off his clothes, tying the fresh Shihakushō around his waist. "Do we spar like before?"
Yamamoto's face darkened. Who had taught this boy to strip whenever fighting? Such impatience would only cause trouble down the road.
"First, to the training hall."
The two walked in line, one old and one young, down the quiet corridors of the squad barracks. The other Shinigami went about their work as if they were invisible, barely glancing at them. Kisaragi Akira's affiliation with the Motoryū in the First Division was no longer a secret, and it seemed word was spreading throughout the Seireitei. Such sights were common for the elite squad members, so they paid it little attention.
The training hall was spacious and bright, the polished floor neatly arranged with simple yet elegant patterns. Kisaragi Akira sat cross-legged, anticipation shining in his eyes as he faced the elder.
"After these days of sparring and training… your weaknesses have been corrected somewhat, but new problems have emerged," Yamamoto said, hands clasped behind his back, his deep voice commanding respect without even trying.
"From your fight with Shiraki Shin'ichi, it's clear you have combat experience, but your fundamentals remain thin. Both your awareness and control are somewhat distorted."
He raised his right hand, fingers splayed, and then snapped them shut at a speed too fast to follow. The air in his palm exploded, sending a fierce gust that made Kisaragi Akira's chest tighten.
"Against someone of equal level or strength, you could rely on your spirit body to crush them. But when facing someone truly skilled, the results are uncertain."
Kisaragi Akira frowned, skeptical of the claim, but seeing the massive fist in front of him—like a clay pot the size of a small boulder—he decided to keep quiet for now.
"You do have talent," Yamamoto continued, ignoring the boy's expression. "Set aside the resilience of your spirit body, and we have the Shiken-ryū taught by Captain Unohana—foundational techniques for the Seireitei. Alongside that, there's the secret Shiraki-ryū of the Shihōin family, though it's wholly incompatible with you."
"Remember, the Shihōin family oversees the covert mobile units. Their tactics and combat style are assassination-based. Of course, you've already covered in a short time what normally takes years or decades. That alone speaks volumes."
"Indeed, mastering these skills is for combat purposes. In terms of fighting ability, you're more than competent, even excellent."
Yamamoto paused, watching Kisaragi Akira's reaction closely. Finding none, he continued:
"Your current state is like wearing someone else's clothes and shoes. They fit, but psychologically, there's a mismatch. Previously, you may not have noticed, but now, having entered Motoryū properly and learned Tsubade and Kōatsu… you must have felt something was off, right?"
Kisaragi Akira fell silent. Truly, the old master could spot the smallest discrepancies at a glance. Even minor discomfort and disharmony were instantly detected. These subtle issues were exactly why Kisaragi Akira had faltered under Senjumaru's entanglement; he could have held out a little longer if not for them. Yamamoto's insight hit the mark precisely.
The Shiraki-ryū and its assassination methods complement each other, leading most of the family to develop unique spirit structures. Kisaragi Akira's explosive, clothes-tearing style was simply not on the same wavelength, so mismatches were natural. These weren't just stylistic differences—they were countless minute details: height, weight, limb length, stride width… Refining all of this to perfection would take three to five years at least, even for someone with extraordinary talent.
"Understood," Kisaragi Akira sighed. "I'll try to avoid using it from now on."
Yamamoto shook his head. "There's a better way."
"Tell me!" Kisaragi Akira perked up.
"Simple," Yamamoto said, his bald head creaking as he turned, faintly amused, a subtle, almost sinister grin forming. "The best way to fix errors isn't by patching them. You crush them utterly, like toppling a leaning building. Tear it down and rebuild—it corrects everything!"
Kisaragi Akira stared. …So this old man just wants to punch me, huh? True to form, Yamamoto was simply raising the difficulty because Kisaragi Akira had been too pampered before. Reasonable as it sounded, the boy suspected some personal grudge mixed in.
Seeing no objection, Yamamoto stripped his Shihakushō and tied it around his waist, revealing a body covered in scars, radiating an intimidating aura. Perfect—another mark for the "remember grudges" ledger.
As Kisaragi Akira readied himself, Yamamoto clenched his massive hand, sending forth a scorching whirlwind. For once, he struck first. In an instant, the elder's aged face was nearly upon him, followed by a fist the size of a cauldron.
Kisaragi Akira's pupils shrank; he hadn't yet reacted.
Boom—
Nightmare unleashed!
Time seemed to stretch as the training hall was reduced to rubble. The floor was shattered, walls pockmarked with massive holes. Kisaragi Akira lay flat among the debris, eyes vacant, raising the only usable right hand to activate reiryoku recovery.
Meanwhile, Yamamoto stood lightly, sweat beading on his forehead but otherwise unharmed. Despite Kisaragi Akira's best efforts, he hadn't inflicted even a scratch. Yet the lesson was effective.
As Yamamoto had said: tear down the crooked building and rebuild. He spent the entire afternoon smashing Kisaragi Akira's bad habits to pieces. Kisaragi Akira's combat awareness was rebuilt from the ground up, though his body looked a little worse for wear.
During the session, Yamamoto repeatedly demonstrated Ikkotsu's power flow, combining spirit and reiatsu into a tailored combat method. The technique's strength relied on the user's spirit body and reiatsu—exactly what Kisaragi Akira needed.
The only issue: Kisaragi Akira wasn't yet strong enough to use it perfectly. Overexertion could seriously backfire.
Yamamoto dragged him from the rubble, dusted him off, checked him over, and casually dropped him back on the floor.
"Similar training sessions may happen frequently," he warned. "Of course, only if new flaws appear. Regarding Ikkotsu, come to me in the First Division if you're unsure. Do not improvise. Today, you performed well; your previous mistakes are forgiven."
Kisaragi Akira furrowed his brow. Mistakes? The old man clearly held a grudge. Given the gap in strength, he marked another point in his personal ledger. Someday…
"Another thing," Yamamoto said, his expression serious. "Remember the assassination attempt at Zenteiji?"
Kisaragi Akira paused, recalling: "Ah, yes. A rebel strike team ambushed me while I was exhausted…"
Yamamoto remained silent. Exhausted, huh? After I pounded you all afternoon and you're still alive, and you call that exhaustion?
"After you left, multiple squads investigated the Hollow in Zenteiji. At the same time, another batch of black-clad figures appeared. They were clearly there to kill witnesses. I suspect the Hollow in Ryuhon Street may be connected to the rebels."
Kisaragi Akira listened intently, bruises forgotten. "Then?"
Yamamoto glared, continuing: "The Seireitei side suffered heavy losses. The rebels were wiped out. The covert units investigated and found evidence of a possible third party. Based on their reiatsu, this unknown was at least vice-captain level."
Kisaragi Akira considered this. A third, unknown force amidst Seireitei, rebels, and nobles' disputes. Even without outside invaders, the Soul Society was a boiling mess.
"Recently," Yamamoto continued, "there have been disappearances in Ryuhon Street, including both Shinigami and civilians. Similar reiatsu traces were found. I intended to assign Kyōraku, but he had urgent matters. Ukitake is bedridden. So…" He looked down at Kisaragi Akira. "You, with your free time, shall investigate."
Kisaragi Akira's eyes widened. Me? Was the old man out of his mind, sending a member of the Eleventh Division on such a delicate mission?
"Any objections?" Yamamoto's voice was calm, yet heavy with pressure. A single word of refusal, and that massive fist would descend.
Kisaragi Akira inhaled, reluctantly accepting the task. Yamamoto had genuinely entrusted him—a rare gesture. The boy's resolve solidified: honor the trust with sincerity.
"Don't forget to stop by the Fourth Division first," Yamamoto added. "Let Captain Unohana check you over to avoid internal injuries…"
The voice drifted away, leaving the hall empty. Kisaragi Akira's lips curled into a faint smile. Perhaps there was something to look forward to, and his steps grew lighter.
…
Fourth Division, General Medical Ward.
Upon arrival, Unohana temporarily set aside her work to check Kisaragi Akira. Lying on the bed, he weakly recounted Yamamoto's harsh training and then mentioned the new assignment.
Unohana already knew some details.
"The Twelfth Division members sent to Zenteiji returned strangely excited, claiming newfound strength. They requested transfers to the Eleventh Division."
Kisaragi Akira's lips twitched. Transfer wasn't that simple—approval or testing was required. A bunch of researchers going head-to-head with brutes? Brains were going to get smashed.
Unohana smiled, gently turning Kisaragi Akira over. Her delicate hands applied medicinal ointment to the bruises, the cooling sensation easing the pain. The effect was remarkable; swelling and soreness visibly diminished.
"If you're going to investigate," she said softly, "start in the North Ryuhon Street, District 54. You may find clues there…"