For the next three days, Minato accompanied Naruto as he practiced the Rasengan. With the support of Multiple Shadow Clones, Naruto's training progress was lightning fast. In just two and a half days, he burst the water balloon with one hand, passing the first stage of Rasengan training. This was also thanks to the Nine-Tailed not disrupting his Chakra; otherwise, even if Naruto were given another $2.5$ years, it would likely have been difficult to achieve this goal.
In Minato's view, Naruto's talent was not low. His performance as a dead last in the original story was mainly due to the Nine-Tailed. Furthermore, while Naruto hadn't fully inherited the Uzumaki Clan's talent, he had perfectly inherited Minato's own outstanding reflexes. Being fast and having fast reaction speeds are two completely different things. As the saying goes, anyone can hit the gas on a straightaway, but being fast in the corners is true speed!
In the original story, as soon as Naruto learned the Nine-Tailed Chakra Mode, he was able to narrowly dodge the Fourth Raikage's point-blank output, proving he had an exceptional talent for reaction speed. Especially since his father was famous throughout the Ninja World for his speed, even if it was just following a pattern, he should at least let Naruto try to learn the Flying Thunder God. Instead, Naruto was made to learn those damn Shadow Clones, which lowered the main body's Chakra and led to him being overwhelmed by enemies in various ways. Without a doubt, this was definitely still due to his status as a Jinchuriki.
"Naruto, come spar with me. Let me see what level your current strength is at."
Training requires a balance of work and rest. In particular, the Rasengan requires Chakra to rotate at high speeds through the wrist; overtraining would place a heavy burden on the Meridians. With the first stage of training complete, Minato wasn't in a hurry to have Naruto start the second stage. Instead, he intended to guide Naruto's combat skills.
"Oh! Let's go!"
Without a second word, Naruto created dozens of Shadow Clones with a poof. Seeing this, Minato sighed and raised his hand without hesitation.
"Stop! Why did you create so many Shadow Clones?"
Minato couldn't understand it; he had wanted to ask this question back when he watched Naruto.
"Eh? What's wrong? More people means more power, obviously! Fifty against one, the advantage is mine!"
Naruto said without thinking, looking full of confidence.
"Who told you that more people necessarily means more power?"
Minato facepalmed helplessly. Although his Chakra control had improved, this kid was practically illiterate when it came to theory.
"Listen closely, Naruto. The original intention behind the invention of the Shadow Clone was to obtain information more safely and conveniently through consciousness transfer. But relatively speaking, Shadow Clones aren't suited for combat because the technique has a fatal flaw: it evenly divides your main body's Chakra! If you create $100$ Shadow Clones, your main body will have less than $1\%$ of its Chakra left. Even if the Chakra from destroyed clones flows back, they will all dissipate before long. It's equivalent to wasting all your Chakra as soon as the battle starts."
"...Is that so?"
Naruto scratched his head. Currently, he still couldn't distinguish between Chakra and having a lot of Chakra. What Minato was saying was a bit difficult for him to grasp. However, this didn't mean Naruto was stupid. From some of his reactions in the original story, it wasn't hard to see that he was actually quite perceptive; he just suffered from a lack of education.
"You rely too much on Shadow Clones. It's best not to easily release techniques like the Shadow Clone during battle. For a Ninja, insufficient Chakra is fatal."
Minato warned him solemnly. With the way Naruto fought in the original story, he only survived because of his Protagonist Halo. Few enemies were truly out for his life; anyone else would have died a hundred times over. If nothing else, take the encounter with Zabuza. If Haku had any killing intent, Naruto wouldn't have lasted long enough to tap into his power. A Hidden Mist Jutsu plus a basic attack would have slit his throat.
"Even a technique like the Shadow Clone can serve as a trump card if used well. In a direct confrontation, especially against an opponent of similar level, it's best not to use more than $4$ Shadow Clones. Even if you create $1,000$, you're only operating at $0.1\%$ of your strength. While it can wear down an enemy's stamina to some extent, the fatigue experienced by the clones is fed back to you. This way, you not only consume the same amount of physical energy, but you also endure more pain and mental stress than the enemy."
"Then what should I do? All I know is this Shadow Clone thing," Naruto pouted.
"Who told you not to pay attention in class?"
Minato looked at Naruto with a half-smile. The required standard for the Ninja Academy is mastering the Three Basic Jutsu. This gave many people the illusion that nothing useful could be learned at the Ninja Academy. In fact, the opposite was true. The Ninja Academy taught many basic yet practical D-rank elemental techniques.
In his previous life, there were conspiracy theories online saying that Ninjutsu was monopolized by the major hidden villages and clans. This was both right and wrong. Certain important Ninjutsu and forbidden techniques certainly wouldn't be circulated publicly. This had nothing to do with a monopoly; Ninjutsu was part of strategic resources, and a critical part at that. But some inconsequential Ninjutsu, like the common Shadow Clone, Great Breakthrough, or Great Fireball, weren't actually that hard to get a hold of.
Because $90\%$ of people in this world didn't have the Aptitude to become a Ninja and could only mobilize a small amount of Chakra, the leakage of such Ninjutsu had little impact even if they spread. Furthermore, everyone has different styles they excel at. For instance, among the Konoha 11, none of them knew Earth Release. They didn't even know basic techniques like Earth Style Wall or Hiding Like a Mole; one couldn't say Konoha didn't possess such Ninjutsu. In reality, for Ninjas who fight in teams, someone like Minato, who learns a bit of everything just in case, was the outlier.
With the cheat code that was the Shadow Clone, Minato was confident that in the short term, he could help Naruto achieve at least one Chakra Nature Transformation on top of learning the Rasengan and Flying Thunder God. While the father and son were training earnestly, a tall man with white hair, wearing a red haori, arrived at the Training Ground.
"It really has been a long time since I've been back—"
Watching the two figures training, Jiraiya's expression was complex, his tone carrying a hint of sentimentality. "Those are truly nostalgic faces."
"Hm? Jiraiya Senior?"
Sensing Jiraiya's gaze, Minato, who was teaching Naruto in the Training Ground, turned his head. Seeing Jiraiya, he froze slightly and showed a perfectly timed look of surprise.
"Jiraiya... Senior?"
Hearing Minato's address, Jiraiya was also stunned. Why Senior?
"Aren't you my Disciple?"
Jiraiya pointed at himself in bewilderment, then seemed to remember something and slapped his palm. "I remember now, you were assigned to my squad after graduation—"
"No, I graduated early. And my teacher was Tsunade."
Minato shook his head.
"Huh?"
Hearing this, Jiraiya was dumbfounded. Immediately, a thought flashed through his mind—Konoha is finished!
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