The "First Bone" is a hand-to-hand combat technique created by Yamamoto Genryūsai Shigekuni.
It is recorded as "basic" content.
Yes — even though the technique was created by the Commander-General himself, it held nothing noble or complex, being classified as part of fundamental training.
And the reason for this…
Was simple and straightforward.
The "First Bone" consisted only of using all the muscles and the body's spiritual pressure to propel the right fist at maximum speed.
No frills, no tricks,
Only through hard practice and sweat could it be refined and honed to perfection.
That's why it appeared early in the academy manuals, remembered by many students as one of the essential foundations.
But precisely because of this——
"Most people tend to underestimate this technique."
Arima Shinya let out a long sigh, exhaling the heavy air from his lungs.
He slowly lowered his arms, still covered with remnants of bluish spiritual particles, lightly dancing around his hands like fish swimming in circles.
The young man adjusted his stance, facing the stunned Ōmaeda in front of him with a calm smile.
"Senpai, I suppose after you graduated, you also set aside hand-to-hand combat training, right?"
After all, anyone who studied it deeply would easily realize——
"When the 'First Bone' is activated, the flow of muscle movement and spiritual pressure is smooth, allowing an immediate transition to the next stage: the 'Double Bone.'"
One strike that doesn't break,
Another that pierces.
That was the true essence of the technique.
Arima Shinya curved his lips slightly in a smile.
Instinctively, he tried to brush a strand of hair off his forehead, but before finishing the gesture, his face twisted in pain.
"Ouch, ouch, ouch…"
The "Double Bone" he had prepared didn't reach the enemy.
At the last moment, Arima restrained the advance with force.
The strike didn't touch Ōmaeda's body, but in return, the recoiling energy hit him squarely — his hands reddened, tingling with pain.
Ōmaeda Nishinjin opened his mouth, taking several deep breaths.
"You… why did you do that?"
"Ōmaeda-senpai, we hold no grudges, right?"
Arima gave a light smile and answered firmly:
"It was only a duel, not a fight to the death. The victory has already been decided, and that's enough. Besides, a commotion like this has already gone far enough today."
Continuing to fight would bring nothing good.
Making the vice-captain of the 2nd Division fall in a humiliating way would only embarrass both of them.
In the end, it would only spread the story as a farce, making Arima Shinya's name even more talked about among the students.
Acting on impulse and hurting someone unnecessarily would be childish and foolish.
"Ōmaeda-senpai, I just want to study in peace… I don't want to draw any more attention."
There were still over a hundred years left until the main story began.
Arima Shinya was in no hurry.
All he wanted was to proceed step by step, savoring the process of becoming stronger.
That was his foundation, his understanding of true growth.
Of course, Arima also had his own plans in mind.
He blinked lightly, smiling mischievously at Ōmaeda.
"Senpai, for today, I hope… from now on, you'll give me a little help once in a while, alright?"
The surname Ōmaeda might not be as grand as the Four Great Houses,
but his family still held power and influence of its own.
Without exaggeration — even if Nishinjin abandoned his post and returned home, he would still be a man of means…
A "sponsor" like that could only bring benefits to Arima Shinya.
While Ōmaeda was still processing what had happened, Yoruichi Shihōin leapt onto the stage.
As head of the Shihōin House, her presence was truly imposing.
Even among two men over one meter eighty, Yoruichi radiated an incomparable aura.
She lifted her chin, raised Arima Shinya's left arm, and declared loudly for all to hear:
"In the name of the Shihōin House, I declare — the winner of this duel is Arima Shinya!"
"Ehh? How did it come to this…?"
"Ah, well…"
The protagonist still tried to say something,
but seeing Yoruichi's sharp gaze, he swallowed the words before they came out.
He might be able to defeat a vice-captain using tricks,
but facing the head of the Shihōin House? No way.
Fighting, arguing — impossible.
And if this unpredictable woman decided to just knock him out for fun…?
"So this is how my peaceful student life ends…?"
Even though it was only an exchange of hand-to-hand strikes, both had used spiritual pressure — making the duel far more serious.
Watching the audience in ecstasy, Arima Shinya could only force an awkward smile.
Everything had turned into a complete mess!
"Hey, Arima Shinya."
Yoruichi's voice sounded beside him.
Turning slightly, he saw her observing him with a curious, almost enchanted gaze.
After a few seconds of silence, she spoke:
"Are you interested in becoming the son-in-law of the Shihōin House?"
"…Huh?"
…
One day later.
"So, what was your answer?"
At night, after the kenjutsu training, Arima Shinya and Tōsen Kaname sat side by side, drinking green tea from plastic bottles — a custom after training.
"Of course I refused! Are you crazy? If I had accepted, do you think I'd still be here now?"
"Makes sense."
Tōsen set down his bottle, turning his face to Arima with attention.
"But why refuse? Marrying into the Shihōin House would only bring benefits."
"Noble families have resources we commoners will never have.
Besides, Yoruichi saw potential in you — she certainly wouldn't be stingy."
"Arima, from your perspective, I see no reason to refuse."
The protagonist frowned, making a grimace.
"You're so opportunistic, Tōsen. I'm not a giant panda — what I want isn't reproduction, it's love."
And more…
"After marriage, I wouldn't even choose who I'd be with. The women of the Shihōin House are beautiful, yes, but who knows what could go wrong."
Tōsen remained silent for a moment, then asked:
"Giant panda?"
"…A rare, protected animal. Forget it, I said something silly!"
Arima remembered that Yoruichi had a brother — similar in appearance and with a somewhat delicate air…
With potential to become a trap.
But Arima definitely had no interest in that.
No traps! Never!
Of course, these were just the most superficial reasons.
Deep down——
"I just prefer to keep living this way."
Arima Shinya smiled at Tōsen, filled with mixed feelings.
Yoruichi's sudden invitation had been a surprise,
but thinking calmly, he realized it was truly a trap.
If he really became a family son-in-law, he would completely lose contact with Aizen.
And more — it would become much harder to get close to the 13th Protection Division.
A noble son-in-law had no freedom — especially in a feudal system like that.
At best, he would end up caged like a golden canary.
He couldn't act on impulse and regret it later.
Besides, he really had nothing to complain about in his current life.
In kenjutsu, Tōsen had captain-level talent.
Training with him was the most solid way to improve his sword attributes.
The other three areas still lacked a fixed routine,
but staying at the academy, sooner or later, he would find opportunities.
And with "Professor Aizen" always nearby — it was just a matter of asking when doubts arose.
Could the Shihōin House offer that kind of support?
Of course not!
While reflecting, Arima suddenly heard Tōsen say:
"Arima… sorry."
"…Huh? Why are you apologizing out of nowhere?"
Tōsen lowered his head, silent for a few seconds, before whispering:
"As a friend, I didn't reach out when you needed it most. I failed my own conscience… and betrayed my principles."
He had always said he should never fear authority — but the moment Arima was pressured, he hesitated.
Even if the outcome was positive, something within him bothered him.
"I haven't changed anything… I thought I had evolved, but I still feel fear and insecurity."
Arima Shinya looked at him, surprised.
After a brief silence, he replied calmly:
"It's fine. In my place, I would have done the same."
"But that's wrong!"
Tōsen's voice rose.
His hands trembled slightly, his entire body tense.
"I didn't come here out of convenience. I have a purpose — I want to become stronger to find true justice!"
"Hey, Tōsen."
Arima interrupted without ceremony, lifting his gaze to the sky and smiling.
"I've told you something similar before, haven't I? Don't cling so much to the present.
When you grow and have enough strength to follow your own will, that will already be enough."
"Justice, equality — whatever it is. If those are your ideals, then keep believing in them."
"Face suffering and doubts as part of training. That way, perhaps your heart will feel lighter."
Laughing, Arima gave a gentle pat on his friend's shoulder.
"And as for the rest… ah, please, Tōsen, no need to apologize so much."
After all——
"We're friends, aren't we?"