Gin's 'Fist Bone' was learned from Sage.
After mastering the Six Styles and comprehending Haki, and boosting his power significantly by eating a fruit, he needed to train in other skills, so Gin began learning the techniques of 'Fist Bone' with Sage.
It's not that Sage wouldn't teach North Star Divine Fist; that's something that can't be taught, as it is his special skill, like the Secret Hole Strike; rather than saying it's the human body's structure, it's more like his unique secret.
Even the strongest Observation can't see it.
What can be taught are only the skills one should have on the sea.
Gin specializes in body techniques and can learn skills that rely purely on the body to strike hard objects, thereby achieving physique enhancement.
In Sage's view, although Gin may not have the two-hundred-times Spirit Time House, his inherent qualifications aren't too bad; he can still make progress, slowly but surely.
As a high-ranking officer, in Sage's eyes, Gin is competent.
At least he truly works hard, practicing day and night to grasp these techniques, and finally, he's gained some understanding.
When transformed into combat power, he can independently handle challenges elsewhere.
Take the current campaign to conquer Whitebeard's territory, for instance. Captain-level officers certainly need to experience trials one by one, while high-ranking officers can act purely based on their own will, as long as they don't fall behind.
Gin is definitely leading the team; aside from training daily, he maintains order at the port. He used to encounter some troublemakers among the pirates, but as Master Sage becomes more stable, those troublemakers among the pirates have decreased.
It's not that he can't stay idle; he's mainly useless outside of combat, can't even understand taxes, truly clueless on what to do, when Master Sage decided to seize Whitebeard's territory, he was the first to respond.
He'd rather fight pirates outside than haggle over taxes and goods with the merchants on the island.
With Whitebeard dead, resolving island matters is easier; now the Whitebeard Pirates lack their former cohesion, the traumatic impact of the Summit War is huge. Aside from scattering, those ambitious other pirates are also surging into Whitebeard's territory, capturing numerous islands and occupying them.
But for Gin, this doesn't matter; whether it's Whitebeard or not isn't important, completing Master Sage's plan is what matters.
One island, two islands, three islands...
As long as it's on the route, any island encountered in the plan, Gin won't let any go, after conquering, he'll first plant the flag before anything else.
As for strict control, they can't station personnel on every island because they are short on staff. Master Sage set the target: for any discovered island, first eliminate the local ruler, and deal with the rest later.
A month later.
The dual-masted pirate ship Gin was on entered a foggy sea area.
"Where is this?" Gin frowned, looking at the navigator beside him.
"Master Gin, just ahead, it should be the Magnetic Field Island Celent, on the same route as O'Hara."
The navigator looked around at the surrounding fog and frowned too, "Strange, I remember there's no fog here, climate change maybe?"
The navigator was a newly joined pirate, having previously been active in the nearby area, thus fairly familiar with the place.
However familiar, he couldn't know exactly how many islands lie between the Magnetic Field Islands; undiscovered islands always exist, even in the Grand Line.
Sage knew of such circumstances, so his orders, aside from occupying the territory left by Whitebeard, were also to expand influence, ensuring the sea recognizes the area he delineated, which is enough.
But for these islands, they don't have enough Eternal Poses, thus relying on the Log Pose for directions to the next island, combined with other pirates' intelligence, to occupy territories.
"Forget it, it's not important, this island is also Master Sage's target. Let's go." Gin said in a deep voice.
Within the fog, the dual-masted pirate ship rushed towards the outline of the island revealed within the mist.
...
In a seaside cliff cave on O'Hara Main Island, holding a Golden Fishing Rod and wearing a Golden Straw Hat, Sage sat unwaveringly at the cave entrance, staring at the fish bobber below.
This was his fifteenth time changing locations.
He heard earlier that there's fish at the Vice Island's lake, fulfilling expectations wonderfully... he didn't catch a single fish.
After breaking two Golden Rods, he began to move to other places.
Vice Island has a flat terrain; it's better than the mountainous main island, with villages near the coast that often fish at sea. From an agricultural perspective, it's a place suitable for both farming and fishing.
So Sage didn't believe in impossibilities; on the coast, where one sweep of a net catches fish, he refused to believe he couldn't catch a single fish; if he truly didn't catch anything, then it was just a place incompatible with him, he would simply switch to another location.
Then he discovered, hmm... maybe the entire Vice Island is somewhat incompatible.
But Sage possesses immense willpower, never fearing failure, and truly is the first stubborn species without exaggeration.
If this place isn't suitable, then he'll find another location; as long as there's a place to fish, the Fishing King will find a way to reach it, no matter where it is.
For example, this cliff cave by the sea, he could maneuver into using Moon Step!
"Boru boru boru..."
The portable radio snail on him suddenly rang, Sage casually picked up the receiver, "Who is it?"
The radio snail embodied a stubborn, serious expression, "Sage, something's happened!"
It's Lily.
"Hmm?" Sage glanced at the fish bobber, "What's wrong? Did Kaido attack?"
"No, it's Gin..."
Lily paused, then added, "Reports came in, Gin is currently trapped in Celent, can't get out."
"What happened?" Sage furrowed his brows.
"I don't know, those people are extremely scared and can't speak clearly, and there's static, even the radio snail has no signal. I'll go take a look myself."
"Hmm... Forget it, I'll go myself. Gin is trapped; just in case, I'll also go. Lily, prepare the ship."
Sage hung up the phone, casually tossed the fishing rod aside, glanced at the fish shadows reflected on the sea below, and said fiercely, "Wait for me, I'll catch all of you sooner or later!"
Saying so, he stepped forward, creating a burst of smoke rings in the air, heading towards Storm City.
When Sage arrived, the Death Star was already prepared, and Sage entered the deck, directly heading to the captain's cabin.
"Yo-ho, everyone's here?"
Just entering the captain's cabin, Sage saw several high-ranking officers filing in, besides the standard three female officers, except for Moriah, other high-ranking officers had also gathered.
Moriah was too lazy to move unless absolutely necessary; he never wanted to leave his residence. Besides having a room in the Royal Palace, he even built a castle on Vice Island, staying there carefree in his free time.
Hawkins was there drawing Tarot Cards, "This time Gin has a problem, we'll go check too... Hmm, his survival rate is 70%, he'll be fine. But judging from the cards, it seems like he's entangled with something."
He turned over a card, "The reverse of [Strength], it looks like he's afraid of something, though there are other cards too. In combination, it suggests he's troubled by fear while seeking escape."
"Whatever, we'll go check it out. Lily, which place was it?" Sage asked.
"Celent."
Lily said, "From here, it's the second Magnetic Field Island; going directly there would take half a month. We don't have an Eternal Pose, but we have extra Log Poses so we can go directly there."
On this island, there are quite a few people with Log Poses, and they've stored enough themselves, so they can proceed directly to that place.
"This island originally belonged to Whitebeard's territory; as a Magnetic Field Island, there's a kingdom on it, a principality under Whitebeard's protection... But I reviewed the reports; no notable individuals exist within the country, and I don't know what's up with Gin." Lily explained.
Even needing subordinates to make the call?
Even if there are remnants of Whitebeard's men, it shouldn't be to the extent that a call can't be made.