"How far it can fly depends on the height and the initial velocity of its flight…"
"Let's use this problem as an example. As a Ninja, you are standing at a height of 5 meters and you throw a shuriken with an initial horizontal velocity of 100 meters per second. How far will it travel before it finally lands?"
Uzumaki Naruto could only stammer, "Uh… uh… uh…"
"What in the world! I don't get any of this!"
[Please, Host, listen and learn with full concentration. Otherwise, you will receive a baptism of Lightning Release from the System…]
[Warning, countdown 5… 4… 3… 2…]
"Aah, I get it, I get it!"
Uzumaki Naruto rubbed his cheeks vigorously, once again forcing himself into a state of total focus.
"Throwing a shuriken forward, initial horizontal velocity of 100 meters per second, what's the final distance…"
"Mm-hmm…"
"Aha! I know! If it's flying at 100 meters per second, then however many seconds it's in the air, it'll travel that many hundreds of meters!"
"The problem is, just how many seconds can it fly for…"
Iruka's gaze swept across the classroom, clearly getting ready to pick a lucky student to answer his question. The classroom instantly fell silent, with every student holding their breath.
Iruka sighed and said with a hint of resignation, "Sakura, you answer it."
"Yes, Iruka-sensei!"
Sakura Haruno answered with confidence, "To calculate the final distance, you must multiply the initial horizontal velocity by the total flight time. The flight time is determined by the height. Considering that the gravitational acceleration in the ninja world is approximately 10, it can be clearly deduced that…"
She spoke with articulate confidence, leaving most of her classmates completely lost. Uzumaki Naruto, naturally, understood even less.
However, unlike before, this time he forced himself to listen with every ounce of his concentration. Even though it all sounded like complete gibberish, he still tried his best, with snot and tears in his eyes, to focus on every single word Sakura Haruno was saying…
Just then.
[You have, for the first time, fully concentrated on listening to the lecture. Your mastery of the [Physics] course has improved. Proficiency +3. Current proficiency is 28 points!]
Uzumaki Naruto was stunned for a moment, then filled with joy!
"This… this can happen too?!"
Although he had just been electrocuted to a crisp, Naruto clearly heard the System's notification. His Physics course proficiency had increased?
While he didn't fully understand what that meant, there was no doubt about it... he had leveled up!
Uzumaki Naruto quickly rubbed his eyes hard, forcing them open as wide as possible, and looked back at the incomprehensible equations on the blackboard. This time, the effect was immediate and outstanding… he still couldn't make sense of it!
However… he also felt like he understood a tiny piece of it!
"Am I actually a genius?!"
Uzumaki Naruto let out two foolish chuckles, a wave of smug satisfaction washing over him.
However…
[Detecting that the Host has departed from a state of full concentration. A baptism of Lightning Release from the System is about to commence…]
[Warning countdown 5… 4… 3…]
Uzumaki Naruto: "…"
He had learned his lesson this time and didn't slack off for a second, immediately forcing himself back into a state of intense focus.
Iruka-sensei smiled slightly. "Very good, Sakura. You truly are the top student in our class."
Sakura was equally pleased with herself. *'Did you see that, Sasuke-kun?'* she thought.
Sasuke remained utterly expressionless. Sakura could only sigh and sit back down in her seat.
"Sakura…"
Uzumaki Naruto saw this scene and was about to let out a sigh when suddenly…
[Warning countdown 5…]
Uzumaki Naruto snapped back. "…Height, initial velocity, gravitational acceleration…"
What was once an ordinary class now felt to Naruto as terrifying as being dragged into an Anbu prison for interrogation! This class was absolute torture!
The short forty-five-minute period became the longest stretch of time in Naruto's young life. Single-minded, full concentration! It sounds simple, but for a boy like Naruto, who was accustomed to being lazy and playful, it was an almost impossible task!
Although he desperately forced himself to listen carefully out of sheer terror of the "baptism of Lightning Release," he still couldn't stop his mind from wandering… sometimes he'd want to steal a glance at Sakura Haruno… sometimes he couldn't resist cursing Sasuke under his breath… sometimes his stomach would rumble, and the heavenly image of Ichiraku's ramen would swirl in his mind…
But each time his thoughts drifted, the piercing warning from the System would sound, forcing him to snap back to reality. He felt like he was sitting on a bed of nails, with every second feeling like an entire year.
This state lasted for what felt like an eternity.
Finally… he endured it until the moment Iruka-sensei announced the end of class.
Uzumaki Naruto felt as if he had just run three marathons; he instantly deflated like a popped balloon and collapsed with a thud onto his desk.
Seeing this, Iruka-sensei actually showed a faint smile.
*'That Naruto, he really didn't cause any trouble this entire class…'*
*'And his eyes were wide open the whole time; it looked like he was genuinely listening to the lecture…'*
*'It seems my heartfelt advice actually had some effect!'*
He cleared his throat. "Alright, a ten-minute break. The next period is Mizuki-sensei's chemistry class!"
"Aww—"
The classroom immediately filled with groans. But Naruto didn't even have the energy left to groan…
Just then.
[According to this System's schedule, break time is the best opportunity to surpass your rivals!]
[Please begin cultivating the Chakra Refining Technique immediately!]
[The current daily practice time for the Chakra Refining Technique must not be less than eight hours!]
Naruto's jaw dropped. "…Are you serious right now?! Eight hours?! Am I not supposed to sleep?!"
[Detecting that the Host has not begun training according to the System's schedule. A baptism of Lightning Release is about to be initiated…]
[Warning countdown, 5… 4… 3…]
"Ahhh! Fine, I'll train, alright?!"
Although Naruto was mentally and physically drained, the memory of the terrifying Lightning Release baptism was enough to make him force himself to sit still and begin practicing the basic Chakra Refining Technique taught at the Ninja Academy.
The so-called Chakra Refining Technique is the process of extracting both physical and spiritual energy from one's body, mixing and refining them to transform them into controllable Chakra. To be more precise, the mixture of physical and spiritual energy produced by a Ninja's 130 trillion body cells is not Chakra, but stamina. Stamina exists in everyone's body, not just in ninjas.
Stamina is also the foundation for activating Taijutsu. Of course, Taijutsu can also be enhanced with Chakra to increase its power. To activate Ninjutsu and Genjutsu, one's stamina must first be converted into Chakra. The technique taught at the academy is essentially training to convert stamina into Chakra, which in turn increases one's Chakra "limit"—what is known as Chakra reserves.
As for Chakra control, that comes much later; it's not an ability Naruto could currently manage.
Naruto's Chakra reserves were, of course, enormous. This was not only because the Nine-Tailed Demon Fox sealed within him, through the special Eight Trigrams Sealing Style, was constantly leaking its own Chakra to mix with his. It was also because Naruto inherently possessed the powerful bloodline of the Uzumaki Clan. His Chakra reserves and life force far exceeded those of any ordinary ninja.
At this moment… during the break, everyone else was laughing and playing freely. Sakura Haruno, Ino Yamanaka, and the other girls once again gathered around Sasuke, while the boys were roughhousing in their usual groups.
Only Uzumaki Naruto sat alone in a corner, quietly closing his eyes to begin his cultivation. As he activated the Chakra Refining Technique, his spiritual and physical energies mixed, slowly transforming, thread by thread, into the very Chakra he could use for ninjutsu.
What surprised Naruto was… that he had been utterly exhausted from the previous class. But now, cultivating the Chakra Refining Technique didn't make him more tired. It was actually restoring some of his strength… *'Wow, I guess I am actually a genius as well!'*
[Host has successfully activated the Chakra Refining Technique. Chakra reserves +1…]
Naruto listened to the System's notification in his mind and suddenly felt that this thing might not be so bad after all. Often, people don't try hard enough because they can't see a progress bar. Once progress can be clearly visualized and even quantified, no matter how tedious the task, it provides powerful motivation, and even a sense of pleasure.
Naruto was currently experiencing this exact feeling.
At that moment, Naruto's only two companions at the Ninja Academy, Akimichi Choji and Nara Shikamaru, also stared at him in astonishment.
"Shikamaru, am I seeing things? Is Naruto actually practicing the Chakra Refining Technique during the break?…" Choji asked while munching on chips.
Nara Shikamaru rubbed his sleepy eyes. "Maybe I'm still dreaming… I'll just sleep a bit more…"
Akimichi Choji's eyes were wide as he stuffed his face with potato chips, staring with disbelief.