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It wasn't a large crowd, but the narrow street had plenty of small shops. Beside one of them, the shopkeeper was shifting a heavy box of goods.
"Hello, boss, do you sell water balloons and rubber balls here?" Chen Xing's voice sounded young, but it carried a strangely mature tone.
The shopkeeper, still bent over from moving the box, looked up in mild surprise—hardly expecting a customer so early in the morning.
"Yes, just a moment!" he replied.
He set the box down, disappeared into the shop, and soon returned holding a bag of small water balloons and a standard rubber ball.
"These are water balloons—you can fill them yourself. And here's the ball. How many do you need?" The shopkeeper handed them over, but his gaze lingered on Chen Xing's arm—it bore the distinctive band of a shinobi from Hoshigakure. Clearly, he hadn't expected someone so young to already be a full-fledged ninja.
"For the ball, I want one basket's worth. As for the balloons, I'll take that whole bag you're holding," Chen Xing said, quickly estimating that it would be enough for his purposes.
"A basket's worth?" The shopkeeper blinked in shock.
Anyone watching could probably guess what Chen Xing was planning. Indeed, his goal was to practice the Rasengan—an advanced, A-rank, shape transformation jutsu originally created by the Fourth Hokage, Namikaze Minato. It required no hand seals, but demanded extremely refined chakra control. Chen Xing had been steadily working to improve his fine control over chakra, and this was the next step in his training.
Carrying a full basket of balloons, he headed back toward the Star Clan's training grounds. Along the way, he ran into Summer Star, just as she was practicing flower-style taijutsu.
"What are you doing?" she asked, raising an eyebrow at the sight of the balloons. Normally, Chen Xing would be in the woods training alone.
"Summer Star-sister, I've thought of a special way to use chakra. If it works, the power will be incredible. I'm gathering the materials I need to practice it now."
He didn't hide his intentions—after all, even if Summer Star knew, it wouldn't matter. This technique wasn't a closely-guarded clan secret; its true value lay in execution, not concept.
"Oh? And this technique needs balloons and balls?" she asked, curious despite herself.
"When I was at your place for dinner yesterday, I saw little Somele playing with a ball. I realized—if we could compress chakra into a perfect sphere and make it spin at high speed, it could massively increase its destructive force. And the best part—it wouldn't need hand seals. If I succeed, it could be applied to many situations."
"You're saying you want to shape chakra into a spinning sphere?" Summer Star was surprised.
"Exactly. Look—this ball is harmless when still, but if it spins fast enough, it can kick up dust from the ground. If I could do that with chakra, the impact force would be devastating." Chen Xing took the ball from her, spun it along the ground, and pointed to the dust scattered by its motion.
"This could be a completely seal-less jutsu," Summer Star admitted. "The theory is sound, but making it happen… that's another matter. Maintaining a compressed, rotating sphere of chakra without losing control is incredibly hard."
She knew of the Fourth Hokage by reputation—Konoha's Yellow Flash, a man who had mastered space-time ninjutsu and created the Rasengan. But she had no idea Chen Xing was essentially attempting to recreate that very technique.
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First Stage Training
"I've divided the training into two stages," Chen Xing explained. "Stage one is to form a sphere of chakra inside a water balloon and spin it fast enough to burst the balloon."
Summer Star listened carefully, recognizing the challenge in his voice.
"Stage two," he continued, "is to shape and stabilize chakra into a sphere without the balloon—just pure chakra. Breaking a rubber ball would be the goal for that stage. As for stage three… I'll think about it once I've mastered the first two."
Summer Star was impressed. "You actually created a structured training method for this? I should tell the Hoshikage—you might really succeed."
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Hoshikage's Office
When Summer Star reported the idea, the Third Hoshikage stood up in shock.
"Are you certain this seal-less technique came from Chen Xing himself?"
"I am," she replied. "I never expected him to come up with something like this just from watching a child play with a ball. I'm not sure he can pull it off, but the idea is solid."
The Hoshikage nodded gravely. "If he can perfect it, we'll have a powerful A-rank technique that isn't tied to any elemental nature and requires no hand seals. Do you realize the implications?"
Summer Star's eyes widened. "A… A-rank seal-less jutsu?"
"That's right," the Hoshikage said. "The Fourth Hokage of Konoha created a technique like this. And Chen Xing's method is nearly identical in concept."
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Training in the Woods
Back in his training spot, Chen Xing filled the balloons with water and began the first stage. Chakra swirled in his palm, but the rotation kept collapsing. Hours passed before he finally managed to rupture a balloon through rotational force alone—not the explosive burst he wanted, but progress nonetheless.
"I need chakra to spin around a single point," he muttered. "But controlling multiple directions of rotation at once is too hard. No wonder Naruto in the original Konoha records had to start with multiple hands to guide it."
Still, he refused to use both hands. Mastery with one hand would make the technique truly seal-less and battle-ready.
Summer Star visited later, eyeing the wet ground and torn balloons.
"You've made progress," she observed.
"It's not wrong in theory," he said with a grin. "It's just… getting the chakra to rotate evenly is the hard part."
Three days later, he completed the first stage. The second stage took much longer—over a month to form a stable, high-speed chakra sphere without the balloon.
In just two to three months, Chen Xing had successfully developed the Rasengan. When he demonstrated it, the sheer force shocked both the Hoshikage and Summer Star. They had expected it might take him years—if he ever succeeded at all.
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