After returning home at midnight, Xue Ge gathered his thoughts and resumed his research into adapting ninjutsu to the flow of his own chakra.
The biggest problem with his body was its imbalance. With his right leg and left arm missing, his chakra flow had developed an abnormal tendency, and the slightest mistake could send it out of control. Although it would not damage his body, it made using ninjutsu very difficult.
He had to accommodate that tendency when casting ninjutsu.
As he mulled it over, Xue Ge recalled his conversation with Minato over dinner.
Did simply sending chakra outside the body and then changing its shape count as ninjutsu without hand seals? Then...
Xue Ge flicked his fingers. Several chakra threads shot out, hooked a book on the shelf, and gently set it back down.
Did the chakra threads used to control prosthetic limbs count as ninjutsu without hand seals too? In that case, the category covered a much broader range of techniques.
Moreover, Minato's idea of developing ninjutsu outside the body had given Xue Ge some fresh inspiration.
Since circulating chakra inside my body is such a problem, could I replicate the shape and nature transformations outside it to simulate ninjutsu? In other words... create versions of various ninjutsu that require no hand seals? Pseudo-ninjutsu?
It seemed worth a try...
Just as Xue Ge let his imagination roam, a chill from behind suddenly made his pupils contract.
"How did today go?"
Danzo's slightly hoarse voice sounded behind him. Xue Ge stiffened a little and answered quietly, "...I made some progress."
"..." Danzo glanced at Xue Ge's desk. The scroll spread across it was covered with notes and drawings of various hand seals and ninjutsu.
"Wind Release: Great Breakthrough? A C-rank ninjutsu. Hmm, it isn't particularly difficult to learn."
Danzo nodded. "So, you're researching this?"
"Yes." Xue Ge nodded obediently. "I'd like to start with offensive ninjutsu. Great Breakthrough requires few seals, which makes it more flexible in combat."
"A good choice." Danzo gave a soft grunt. "How far have you gotten?"
"I understand the basic principles, but..." Xue Ge raised his hand. "My physical limitations prevent me from putting them into practice."
"I see." Danzo stroked his chin. "In that case, let me give you a brief explanation and demonstration."
"Come to think of it, although I took you as my adopted son, I don't seem to have ever taught you anything."
"..." Xue Ge fell silent for a moment. "Lord Danzo, there's something I've never understood."
"Speak."
"Why did you take me as your adopted son?"
"Hmm, that... perhaps it was simply fate." Danzo placed a hand on Xue Ge's head. "Just as I was reflecting on how exceptional Hiruzen's students were, you appeared before me."
"Besides, I could tell that you and I would get along."
"..." Xue Ge rubbed his fingers together.
Danzo took the pen from Xue Ge's hand and began writing on the scroll.
"First, since you already understand the principles behind Great Breakthrough, I can offer some ideas for simplifying its hand seals. You can pursue your research in that direction to make it easier to learn..."
Meanwhile, after returning home, Minato took the balloons he had bought on the way back and hurried straight into the kitchen to fill them with water.
"What are you..." Kushina frowned in confusion at his haste.
"I want to test a theory." Minato smiled, then carefully picked up a water balloon and fed chakra into it.
As the chakra began to spin, the balloon burst within seconds.
Water splashed all over Minato. Kushina froze for a moment, then hurried over and grabbed his ear.
"Hey, hey, hey! I just wiped down the counter! And look at your clothes!"
"It's fine, it's fine! I'll clean up afterward. You go to bed..."
Facing the Red-Hot Habanero, Minato repeatedly apologized with a placating smile.
"..." Kushina eyed him suspiciously. After a moment, she let go and turned to leave.
"Don't stay up too late. You have a mission outside the village in a few days."
"Right."
After answering Kushina and watching her leave, Minato devoted himself to his water balloons again.
One water balloon after another burst. Gradually, Minato began to see ripples on their surfaces as the water spun and churned inside.
The water balloons took longer and longer to burst, while the water inside spun faster and faster.
The night grew late.
Early the next morning, when Xue Ge arrived at the school gates on time, Minato was already waiting there.
Xue Ge was rather surprised by the heavy dark circles under Minato's eyes.
Before even greeting him, he pointed at his own lower eyelids.
"I didn't sleep at all last night." Minato smiled and shook his head, showing no sign of sleepiness. "But I made quite a bit of progress."
Hearing that, Xue Ge immediately realized something. "The ninjutsu without hand seals?"
"Yes." Minato nodded emphatically. "I've developed a rough prototype. It's still some way from being usable, but I have a clear direction now."
"Could you show me?" As someone who was also developing ninjutsu, Xue Ge wanted to see what a technique without hand seals looked like.
"Of course, but this isn't a good place." Minato casually drew a kunai and spun it around his finger. "Come with me."
The two quickly made their way out of the bustling village and stopped before a small waterfall on the Back Mountain.
Minato walked alone toward a rock jutting from the cliff face.
He raised his hand, and an invisible wind began to swirl. Xue Ge could see something grayish and translucent gathering in Minato's palm.
That was Minato's chakra...
As the chakra spun, a sphere formed. It was still somewhat irregular and looked very unstable, as though it might scatter at any moment.
The next instant, like a flash of lightning, Minato slammed the chakra sphere into the rock before Xue Ge could get a clear look.
Bang!
After a thunderous crack, the rock shattered, leaving a large crater in the cliff face.
"..." Xue Ge's eyes flew wide open.
This... didn't seem quite like the spinning attack he had imagined. After all that spinning, the ball still exploded?
Puzzled, Xue Ge looked at Minato. Seeing his reaction, Minato readily explained:
"After using rotation to shape the chakra into a sphere, you keep compressing it. Then the constant spiraling rapidly grinds through the target's outer structure,
"and the moment you break through that outer layer, you stop compressing it. The chakra sphere instantly expands while still spinning!"
"Of course, it's still very crude. There's plenty of room for improvement," Minato said.
He planned to seek out his teacher, Jiraiya, afterward to discuss how to refine the technique further-how to make it faster to cast and more powerful.
"What's this ninjutsu called?" Xue Ge asked.
Minato paused. He had not considered that question before.
After frowning for a moment, Minato looked at Xue Ge. "What do you think we should name it?"
"The chakra keeps spinning until it forms a ball," Xue Ge said softly. "Spiral Ball?"
"Ball doesn't sound very good." Minato shook his head. "How about Rondo Spiral Flash, First Form: Thunder God Orb?"
"..." The corner of Xue Ge's eye twitched. "Too long. Rasengan."
"That's so short it doesn't sound cool enough." Minato scratched his head.
"Simple is good. Concise is good. Quick to say is good," Xue Ge quipped expressionlessly.
"Hmm... well, all right." Minato shrugged. "Then let's call it Rasengan for now."