After a week of continuous adjustment to his new body, Isamu sat in his dark room, his breathing heavy and erratic.
He stared at the training schedule hanging on the wall, which had been prepared by his grandfather before his passing.
"It seems that life as a descendant of an aristocratic family is no easy feat," he thought bitterly.
This world moves at a completely different pace from the one he knew. Here, children as young as five, especially those from ninja families like his current body, don't just play; they begin physical training early.
Isamu, though only five years old now, based on the memories he had absorbed, had started physical training as early as the age of four.
Under his grandfather's guidance, Isamu had managed to cultivate chakra at an early age. Now, in his new body, he felt a strange power flowing through him more clearly.
That morning, as he struck the tree trunk in the courtyard, Isamu felt it clearly for the first time—the force of chakra flowing through his fist.
The small mark his fist left on the trunk made him stare at his hand in astonishment, feeling the strange flow.
"It's almost like magic," he said quietly, recalling that breathtaking moment.
"This is chakra," he muttered to himself as he tried to understand the changes within him, merging his prior knowledge with the world of Naruto.
Chakra, as he knew it, is an energy resulting from the perfect balance between physical and spiritual energy.
It is the fundamental source that enables ninjas to perform Ninjutsu, Genjutsu (illusion techniques), and Taijutsu. It can also be used in the form of threads to bind enemies or cut through chakra-infused materials.
In the ninja world, chakra is not just a mysterious energy flowing within their bodies; it's a complex process based on the delicate balance between two main types of energy:
Physical Energy (Stamina): This energy is drawn from every cell in the human body, a vital force derived from the body's activity and movement. In this world, a ninja's body contains around 130 trillion cells, a number far exceeding what Isamu knew from his previous life, where the human body had only about 37.2 trillion cells. This vast difference highlights how the physical capabilities of ninjas in this world far surpass what he once understood. Each cell holds a degree of energy that can be harnessed to enhance physical strength, speed, and endurance during battles.
Spiritual Energy: This type of energy is not drawn from the body but is developed and refined through experiences, intensive training, and continuous mental exercises. Every experience a ninja lives, every battle they fight, and every hour spent practicing Ninjutsu contributes to increasing their spiritual energy. This energy reflects the ninja's mental and emotional maturity, granting them better control over their chakra and more effective use of Ninjutsu.
Ninjutsu relies on absorbing and refining these two types of energy in a process known as chakra extraction. Afterward, chakra is activated using hand seals (mudras), which represent the will needed to trigger it.
Once chakra is formed, it flows through specific points in the body known as energy points, similar to acupuncture points in traditional Chinese medicine. These points, numbering 361, are connected by pathways called meridians, which help guide and release chakra in a regulated manner. Ninjas direct chakra through performing hand seals, enabling them to activate different techniques.
To master chakra control, a ninja must maintain a precise balance between physical and spiritual energy.
Chakra can be transformed into strong threads used in battles to immobilize opponents or cut chakra-infused materials. Chakra is also aligned with the five basic elements of nature: fire, water, wind, lightning, and earth, and these elements interact in a specific pattern: fire overpowers wind, wind overpowers earth, earth overpowers water, water overpowers fire, and lightning overpowers earth.
Chakra is the energy created by the balanced interaction between physical and spiritual energy. When the body reaches a certain level of physical strength and aligns with mental energy, chakra can be extracted from the body's cells using special techniques.
The speed of chakra formation depends largely on the individual's talent and continuous effort. However, being born into a noble family does not guarantee exceptional talent in cultivating this energy.
In Konoha, there are many prestigious families known for their strength in the ninja world, such as the Uchiha, Hyuga, and Ino-Shika-Cho families.
The majority of Konoha's elite ninjas come from these families, but this doesn't mean that ordinary civilians have no chance of excelling.
Many of Konoha's greatest ninjas came from humble backgrounds, like the Fourth Hokage, Namikaze Minato, as well as Orochimaru and Jiraiya, two of the "Legendary Sannin," and Maito Gai, who excelled despite his modest origins.
In the world of ninjas, talent in chakra control is a critical factor for success and advancement. However, the ninjas from major clans are often the most renowned and skilled in their techniques, like Uchiha Madara, Uchiha Shisui, and Uchiha Itachi, who displayed extraordinary potential from an early age.
Itachi, for example, was known for his exceptional skills and was only thirteen years old when he played a significant role in the Uchiha clan's annihilation.
Even characters who were initially considered lesser, like Uchiha Obito, achieved remarkable feats at a young age. Obito, who was initially seen as untalented, faced the Fourth Hokage in an epic battle when he was only around fourteen or fifteen years old.
Beyond the Uchiha clan, other families have produced many prominent ninjas who left their mark on the ninja world.
In the world of Naruto, family heritage plays a pivotal role in power and status. While ordinary civilians can advance in society, the strongest and most influential individuals typically come from families with a rich legacy of strength.
Even the protagonist, Uzumaki Naruto, belongs to the famous Uzumaki clan, highlighting the role of lineage in gaining power.
In fact, when reflecting on the original story from a deeper perspective, it becomes clear that the major conflicts revolving around clans like the Uchiha, Senju, and even the Uzumaki are mere manifestations of a larger struggle—the Otsutsuki family conflict.
It can be said that the entire Naruto world is nothing more than a battleground for the bloody wars centered around the legacy of the Otsutsuki family. This legendary family, which emerged in the end as the true source of all conflicts, is the real force controlling the world's fate.
The Otsutsuki family came from outside this world and is responsible for spreading the seeds of chakra and the abilities known to ninjas.
Whether it be the Sharingan, Rinnegan, or even the physical strength possessed by the Senju, all trace their roots back to this family.
Thus, the world we see in Naruto is, in truth, a stage for generations of conflicts between the branches of this family, which continues to impact the world even in the modern generations of ninjas.
Isamu, having been reborn in the body of an Uchiha clan member, feels grateful. He realizes that his fortune in being born into such a powerful clan like the Uchiha has granted him opportunities he wouldn't have had if he had been born as an ordinary person.
In this world that heavily relies on bloodlines and inherited talents, those who lack a strong lineage often become mere fodder for wars and conflicts.
In the ninja world, the method of extracting and refining chakra is not a secret reserved for the elite. Almost everyone knows the basics. However, what sets ninjas apart from civilians is their talent for extracting and controlling chakra.
The challenge lies not in the ability to refine chakra itself but in the speed and efficiency of the refinement process.
This speed in using chakra is what distinguishes the strong from the ordinary, and without talent or family heritage like the Uchiha or Senju, it is difficult for an individual to excel in this harsh world.
The vast majority of people may never master even the simplest Ninjutsu after a period of training, leading many Chunin to rely on kunai and shuriken in battles due to the limited amount of chakra in their bodies, which can be exhausted after using only a few Ninjutsu techniques.
In these circumstances, it is often better to conserve chakra and rely on physical skills in combat.