"Haki?" Nami repeated.
Zoro and Usopp exchanged glances. Both their faces were equally filled with confusion.
Luffy nodded.
"Yeah. Haki."
He propped up his chin for a moment, searching for the easiest way to explain it.
"In different places, people call it by different names. Some call it aura, life force, qi, or other names. But most people know it as Haki."
Luffy raised his palm.
"Everyone actually has Haki."
"But..."
He slowly clenched his fist.
"...most people spend their whole lives never realizing that power even exists, let alone awakening it."
Nami raised an eyebrow.
"Everyone?"
"Yep."
Luffy nodded firmly.
"Haki's divided into three types."
He raised three fingers.
"First, Kenbunshoku Haki."
"This Haki lets you sense the presence of others, pick up on their intentions, and sometimes even know where an opponent's attack is coming before they even move."
"So like a sixth sense?" Usopp asked.
"Pretty much."
Luffy folded down one finger.
"Second, Busoshoku Haki."
"This Haki forms a kind of invisible armor that can coat your body or your weapon. Your attacks get stronger, and your defense goes up too."
He paused for a moment before adding.
"And most importantly..."
"This Haki can actually hit the real body of a Logia Devil Fruit user."
Zoro's eyes lit up instantly.
"That's really useful."
"Yeah."
Luffy raised his last finger.
"Third is Haoshoku Haki."
He scratched his cheek, smiling wryly.
"As for this one... I don't know much about it either."
"What I do know is that only a few people have it."
"How few is few?" Nami asked.
"My grandpa said..."
Luffy looked at each of them in turn.
"...only about one in a million people."
The deck went silent instantly.
Usopp even forgot to blink.
A few seconds later, he quickly raised his hand.
"I've got a question!"
Luffy pointed at him.
"Go ahead, student Usopp."
"Everything you just said..."
Usopp scratched his head.
"Is that all actually real?"
"It's real."
Luffy's answer came without a trace of doubt.
Nami narrowed her eyes.
"How do you know?"
"From my grandpa."
Luffy paused for a moment, then chuckled softly.
"And before you ask why I'm so sure..."
His smile slowly faded.
His expression turned serious.
"I confirmed it myself."
The three of them immediately looked curious.
"For a long time I kept wondering why it hurt so much every time my grandpa punched me."
Luffy unconsciously rubbed his forehead.
Just remembering it was enough to give him chills.
"Every time I asked him why, he'd always answer..."
Luffy imitated Garp's voice.
"'Because my fist is filled with love!'"
Everyone fell silent.
Luffy sighed.
"I actually believed that for a long time."
Usopp stared at him with a flat expression.
"...Are you serious?"
"Yeah."
Nami covered her face with her palm.
"What an idiot."
Luffy pretended not to hear.
"After being fooled for years, he finally admitted it was actually Haki."
Zoro crossed his arms.
"If Haki's that amazing..."
"Why haven't we ever heard of it before?"
Nami and Usopp nodded in agreement.
Luffy thought for a moment before answering.
"Because most Haki users are in the New World."
"The New World?"
"That's the part of the sea that's way more dangerous than the Grand Line."
Luffy's tone grew more serious.
"Out there, Haki isn't anything special."
"If you want to survive, almost every strong fighter has to be able to use at least Kenbunshoku and Busoshoku."
The three of them fell silent again.
For the first time, they truly realized that the sea they'd be facing was far vaster than they'd ever imagined.
Zoro smirked.
"In that case..."
"How do we awaken it?"
Nami and Usopp leaned in closer.
Luffy pointed at his own eye.
"I trained Kenbunshoku Haki the same way I just did with Nami."
"Close your eyes, empty your mind, then sense your opponent's intent to attack."
Then he clenched his fist.
"As for Busoshoku..."
Luffy tapped his own stomach.
"...this part's still just my theory."
"I think you have to keep focusing your resolve on the body part being attacked while imagining energy flowing there."
He grinned widely.
"Which means..."
"You guys need to get hit. A lot."
Silence.
Nami took a step back.
Usopp took two steps back.
"No."
They answered at the same time.
Luffy just laughed a little.
Then he turned to Zoro.
"What about you?"
Zoro grinned right away.
"I'm in."
"Great."
Luffy clenched his fist.
"Focus your mind on your stomach."
"Because that's where I'm going to hit you."
Zoro took a deep breath.
"Go ahead."
THUD!
Luffy's fist slammed into his stomach.
Zoro's body folded up like a shrimp before flying back several meters.
"Ugh...!"
He dropped to his knees, spitting out a mix of saliva and spit.
Nami and Usopp winced along with him.
For some reason, their own stomachs ached just from watching.
Zoro curled up for a moment, holding his breath.
His vision blurred briefly.
He knew Luffy's punches were strong.
But he never expected it to be this strong.
What Zoro didn't know was that Luffy's body had been forged over years of training.
His muscles didn't look as bulky as other fighters', but they were far denser thanks to relentless physical training and the unique nature of his rubber body.
On top of that, Garp had raised him with training that made no sense at all.
Even without Haki, one of Luffy's punches was already enough to shatter a massive boulder.
And just now...
He'd still been holding back.
Luffy hurried over.
"Oi, Zoro! You okay?"
Zoro took a long breath before standing up.
"I can keep going."
He raised his fist.
He grinned.
"Again."
Without warning, Zoro threw his punch.
Thud!
Luffy stepped back twice.
Then punched back.
Thud!
And so their training continued.
Trading blows.
Enduring them.
Getting back up.
Until finally, as noon approached, Zoro collapsed completely onto the deck, breathing hard.
Luffy wiped the sweat from his forehead.
"That's enough for today."
He walked over to the ship's bow and sat down on the sheep figurehead of the Going Merry.
The sea breeze blew gently across his face.
His thoughts drifted back to Garp's stories about Rokushiki.
Soru and Geppo had already proven useful to him.
But the other techniques...
Might be better suited for teaching his friends.
Then there was one technique that kept nagging at his mind.
Seimei Kikan.
A technique that let someone control their body down to every muscle, every organ, even every single strand of hair.
Luffy stared at the sky without blinking.
The more he thought about that technique, the more possibilities came to mind.
Back when he was still training with Garp, he'd once realized something.
Even after successfully developing Gear Second and Gear Third, the gap in strength between him and his grandfather had barely narrowed.
Gear Second drastically increased his speed, while Gear Third gave him incredible destructive power. But after fighting Garp over and over, Luffy realized both techniques only amplified what he already had.
They didn't solve his real problem.
Physical strength.
Compared to Garp or the monsters ruling the seas, his body was still far behind. Even if he someday managed to awaken Haki, that alone might not be enough to close the gap.
He needed something that could improve his body's overall quality.
And that was where Seimei Kikan started catching his interest.
An idea slowly began forming in his mind.
What if he expanded his muscles using Gear Third, then compressed them back down using Seimei Kikan?
Then repeated that same process over and over until he reached the limits of his body's capacity.
Expand.
Compress.
Expand again.
Then compress once more.
If his theory was right, his muscle density would keep increasing without needing to make his body significantly bigger. That way, his physical strength could grow until he could match his grandfather.
Maybe...
That technique could be the bridge he'd been searching for all this time.
Unfortunately, all of it was still just speculation.
He had no idea how to actually learn Seimei Kikan.
He'd once asked Garp to teach him.
The answer he got was always the same.
"That's a secret technique of the World Government."
No matter how hard he begged, Garp always refused.
Luffy let out a slow breath.
In that case...
He'd just have to find his own way.
Over the past several months, he'd kept experimenting with consciously moving the muscles in his body. At first it was just one muscle group, then he slowly tried controlling other parts of his body.
The results weren't visible yet.
But his instincts told him he was heading in the right direction.
As for Rokushiki...
He still had another plan.
If the technique really was taught to members of the World Government and the Navy, there should be some kind of training manual or record explaining it.
The problem was, the Navy base in the East Blue was too small.
He'd never once seen a soldier there use Rokushiki.
Most likely, they simply didn't have access to that technique.
But Loguetown was different.
That city was the gateway to the Grand Line and also one of the most important Navy bases in the East Blue.
If there was any place that held clues about Rokushiki...
It was most likely there.