Spirit Light Jade

Two years passed in the blink of an eye. Jiraiya's rigorous training of the youths had brought them immense growth.

Yuehua Ai was now over eight years old. His appearance and personality remained largely unchanged; he was still a quiet, delicate, and slightly feminine-looking child.

Reflected in the gentle river water was his somewhat slender figure. Yuehua Ai stood quietly by the bank, lost in thought as he watched the occasional whirlpools ripple across the surface.

Time flies so fast, he mused, feeling a sense of melancholy. Because he sensed a certain date approaching, he had spoken to Jiraiya in private a few days ago and obtained his consent for a request.

Once the bandit incident was behind them, Jiraiya had initiated a new phase of training for them—a deeper study of ninjutsu. This phase alone had lasted two years.

This new stage of learning established the path for the youths' development as ninjas. Jiraiya believed in teaching according to one's aptitude. To formulate a plan suitable for each youth, he naturally tested everyone's chakra nature. Although he lacked the simple and direct detection of chakra paper, he was able to determine their affinities by observing their performance and compatibility with various ninjutsu.

Yahiko had a Water-style constitution, Nagato possessed all-nature affinities, and while Konan's chakra did not show a clear elemental leaning, Jiraiya determined she was well-suited for Yin-style ninjutsu.

Yuehua Ai's chakra manifested as both Water and Wind. Water was the most common nature in the Land of Rivers, while Wind was relatively rare. However, even with his dual-nature constitution, Yuehua Ai's raw chakra talent was simply incomparable to Nagato's. To this day, he remembered the shocked and incredulous expression on Jiraiya's face when he first sensed Nagato's potential.

Of course, Nagato's talent had long been within Yuehua Ai's expectations. While he felt a twinge of envy, he had no other strong feelings about it.

Jiraiya excelled in Earth and Fire-style ninjutsu and also possessed profound mastery over Yang-style techniques. Although his affinities did not align with the youths, it did not affect the quality of his teaching. As one of the Sannin, he was already among the elite at the pinnacle of the Ninja World. Even without practicing Wind, Water, or Lightning styles, his insights into ninjutsu cultivation were like looking down from a high vantage point. Furthermore, his educational approach was not a mechanical, spoon-feeding style; he prioritized the youths' self-development and initiative.

Jiraiya's lessons consisted mostly of sharing his own experiences and guiding the youths through the difficulties they encountered during practice. As for the specific methods of learning ninjutsu, his approach was to simply toss the scrolls containing the techniques to the youths and let them study on their own.

Yuehua Ai had now mastered over a dozen Wind and Water-style techniques. Although he had not practiced any high-destruction, large-scale ninjutsu, he felt his current strength was already far beyond that of a genin.

It should be noted that Yuehua Ai's way of learning ninjutsu was different from the others. Compared to their rote practice, he focused on researching the underlying principles. Over these years, he had recorded his insights and the patterns he discovered in scrolls. These records included his summaries on how changes in chakra execution trajectories produced different effects, as well as the varying results of different hand seals combined with different frequencies, flow rates, speeds, and densities of chakra.

The scrolls also contained his hypotheses on variations of known techniques, as well as prototypes for new ninjutsu derived from his summarized experiences.

Yuehua Ai organized and recorded these things mostly out of a habit from his past life of taking notes and keeping a diary. To him, these records were nothing special, but in the eyes of a true expert, their importance was no less than that of a powerful secret or forbidden technique. Although the scrolls he used were ordinary, the language within—which pointed directly to the essence of ninjutsu—had long since elevated them beyond the scope of common scrolls. They were precious, with a value unimaginable to an ordinary ninja.

Because he understood the essence of ninjutsu, few could rival him in its application and variation. A D-rank technique that others could perform at eighty or ninety percent efficiency could be pushed to one hundred and twenty percent in his hands. Thus, among ninjas of the same level, he was undoubtedly at the absolute peak of combat power.

If an ordinary ninja had achieved what Yuehua Ai had, they would certainly be satisfied, but having lived two lives, Yuehua Ai's standards for himself were far beyond what a common "small-fry" ninja could comprehend.

The youths were all genius ninjas. In Jiraiya's eyes, each of his new disciples was no less talented than Minato Namikaze, and among them, Nagato and Yuehua Ai were the ones who satisfied him the most.

Although he had long since gained Jiraiya's recognition, Yuehua Ai felt no pride. His goal, from the very beginning, had been Nagato. No one understood Nagato's talent better than he did. Even though his current achievements had turned heads, he knew they were far from enough to stand before Nagato's potential.

In terms of ninjutsu practice, Yuehua Ai had already far surpassed ordinary people; what limited his power now was his chakra. Despite having a mental talent that surpassed Nagato's, that talent could not be fully converted into raw strength.

Chakra refinement followed the "bucket principle"—it required the mixing of mental energy and physical energy. Yuehua Ai had an incredibly high ceiling for mental energy, but lacking any special constitution, he was strictly limited by the "short board" of his physical energy. No matter how high his mental power was, his chakra refinement was dragged down by his physical energy. Therefore, no matter how hard he refined it, his chakra reserves were ultimately dictated by his physical development.

Chakra was the foundation of all ninjutsu, possessing a superiority that other powers could not match. Even if one's mental power was extraordinary, its pure application remained too narrow. While mental power was untraceable in terms of perception and offered better concealment than chakra, it could not match the level of detail provided by chakra-based sensing.

Don't be fooled by the fact that chakra is merely a collection of two energies; these two energies encompassed almost everything about a ninja—their nature, physical characteristics, and mental traits were all contained within.

Because his chakra was limited, Yuehua Ai shifted more of his energy elsewhere to become stronger faster.

He invested a significant amount of time into swordsmanship and shurikenjutsu. Moreover, while Jiraiya was "feeding" them moves, he managed to learn the Rasengan. Of course, this was self-taught; Jiraiya had not taught it to him specifically.

The Rasengan possessed many advantages and was undoubtedly a leader among A-rank ninjutsu. As a non-seal technique, it was fast and convenient to release, and its concealment and destructive power were unimaginably strong. Compared to the original technique Kakashi prided himself on, the Chidori, it was on a completely different level in terms of practicality, even if it lacked the latter's flashiness.

Jiraiya was not the type to hoard his knowledge. The main reason he hadn't taught the Rasengan to the others was his eldest disciple, Minato Namikaze.

The Rasengan was a technique Minato had taught Jiraiya. Minato had spent three years developing it. With Minato still alive, Jiraiya had no right to pass on the technique to others without permission, even if they were his junior disciples!

Yuehua Ai was quite interested in the Rasengan. Since he couldn't get it taught to him, he had to steal the technique. After watching Jiraiya release it several times, combining his observations of the chakra changes during the process with the information he knew from his past life, Yuehua Ai managed to recreate this non-seal technique after countless experiments. However, he also realized that many things in anime were simply unreliable.

The Rasengan took Minato three years to develop. Given Minato's talent, one could imagine the difficulty involved.

Yuehua Ai didn't realize it until he tried—it was daunting.

The core, the most critical and important part of practicing the Rasengan, was chakra control. Trying to force countless streams of chakra to converge into a high-speed, highly compressed, and incredibly stable sphere—one could imagine the difficulty just by thinking about it.

And that was only considering chakra control. Factors like the forces involved, energy radiation, and the principles of conversion and balance were no easier. It stood to reason that the future Naruto was able to learn the Rasengan not only because he used Shadow Clones to share the pressure, but more so because, as he himself said, if his brain couldn't remember it, his body would. The Rasengan Naruto released was a product of body-memory born from countless failures.

Once Yuehua Ai learned to release the Rasengan, he didn't need to use one hand to condense the chakra and the other to push and compress it back and forth like Naruto did when he first learned it. His release was faster and simpler, not losing out even when compared to Jiraiya.

Although he had mastered the Rasengan, Yuehua Ai never used it in front of Jiraiya, because it wasn't something the man had personally taught him. He would eventually have to visit Konohagakure, and he didn't want his mastery of the Rasengan to create a rift between Minato and Jiraiya. Even if Jiraiya didn't mind and he explained that he had taught himself, would Minato truly believe it? Would he truly not mind? It was like someone spending countless hours and energy on a result, only for it to be quietly utilized by someone else. In such a situation, who wouldn't feel unbalanced?

Yuehua Ai was no novice; he considered many things. He didn't feel the Rasengan was truly his, so unless absolutely necessary, he wouldn't use it. He even instructed Yahiko and the others to keep his mastery of the technique a secret.

The Rasengan was still an incomplete technique; it lacked the addition of nature transformation. Furthermore, it had a major drawback at this stage: it could not be released from the hand during an attack.

Beyond its destructive power, the Rasengan served a more important purpose for Yuehua Ai: it trained his chakra control. It was a technique that pushed shape transformation to the extreme, and it benefited his fine control immensely.

In the days that followed, as his research into ninjutsu deepened and he spent more time secretly using the Rasengan to practice his control, he began to develop more ideas for it.

He wanted to resolve the flaws of the Rasengan and create a powerful, offensive ninjutsu of his own!

With a goal in mind, Yuehua Ai couldn't hold back. After more than a month of work, he combined the knowledge from his past life to modify the Rasengan, making it truly his own. He named this technique the Spirit Light Jade!

The Spirit Light Jade still utilized the concept of high-speed rotation and compression, but it incorporated many elements of physics from his past life.

When it came to rotation, the two things that left the deepest impression on Yuehua Ai were the orbit of planets around stars on a cosmic scale, and the rotation of electrons around the nucleus on a microscopic scale.

Combining the atomic model, Coulomb's law, the Pauli exclusion principle, and various concepts of physics and energy, Yuehua Ai established one core and three foundational principles for his new technique.

He used three main chakra lines as a skeleton, allowing them to exist in three-dimensional space, converging toward the core like a whirlpool. These three routes were both independent small chakra loops and part of a larger chakra cycle. By increasing the chakra injection into these three routes, the chakra at the core would continuously condense and collapse.

The three main chakra lines presented themselves in the ninjutsu space as the most stable triangular pyramid state, and the chakra in each route could perform circular motion, achieving a cycle with the whole.

The initial manifestation of the Spirit Light Jade was the convergence of three wind-like chakra wisps. As the user injected more chakra, the state would continuously compress and stabilize. Once the chakra reached a saturated state, it would form a self-sustaining cycle, presenting a perfect spherical shape like the Rasengan. The difference, besides the Rasengan being blue and the Spirit Light Jade being jade-white, was that the Spirit Light Jade had faint, galaxy-like light diffusing in non-directional patterns around it.

Compared to the Rasengan, the Spirit Light Jade successfully solved the problem of the chakra sphere being unable to leave the hand. It was a large chakra cycle composed of three small, synchronized chakra loops, with the inward-collapsing chakra at the core acting as an anchor and stabilizer.

If the user, without interfering with the core's rotation, released one of the three chakra skeletons as a power source, the Spirit Light Jade could be fired at supersonic speeds.

Because the released Spirit Light Jade broke its most stable state, it could no longer maintain absolute equilibrium despite the remaining two skeletons. Thus, once it encountered an external force, the internal balance would be completely shattered, causing the remaining two main chakra lines to collide and annihilate each other. This would trigger a total explosion of the high-density chakra energy collapsed at the core, releasing all its energy in an instant.

While maintaining overall balance, the Spirit Light Jade could compress more chakra than the original Rasengan, making its power significantly higher. However, it placed much higher demands on the user regarding chakra control and the principles of equilibrium. If one did not understand planetary motion and the atomic model, it would be basically impossible for other ninjas to recreate the Spirit Light Jade.