Naruto: I start with one door, and I can open it infinitely.

When he said goodbye to his mother and was led to school by the retired Chunin, Old Deng, he saw many children doing the same thing. This time, at least there were no more troubles, so he walked into the school with peace of mind and went to his class.

As soon as he entered the classroom, he bumped into a blond-haired guy. They had met by the river before enrolling, and the guy immediately raised his hand to greet him: "Naruto, where are you going?"

"Lin Chuan, I need to go to the toilet," Naruto said without having time to say hello, and then went to the toilet while clutching his butt.

"Tsk, that old pervert Hiruzen Sarutobi, he embezzled Naruto's family fortune. Naruto probably ate expired instant noodles again and got an upset stomach, so he had to run to the toilet," Lin Chuan thought to himself, listing the ten major crimes of old pervert Hiruzen Sarutobi.

Actually, Sarutobi Hiroto wasn't short of a child's living expenses. It was just that no store was willing to sell anything to Naruto, which meant that Naruto could only buy a lot of instant noodles every time, and they would always expire.

He quietly went to his seat, sitting in the last row of the classroom. One of the familiar "Twelve Little Strongmen" sat in front of him, but he still greeted his deskmate first, "Good morning..."

"Good morning," Passerby A replied casually, feeling a little uncomfortable with his classmate's overly familiar manner, even though it was their first time meeting.

"Tsk, they're all strangers," Lin Chuan thought to himself, turning his head to look at the unfamiliar deskmates on his left and right. In this lecture hall, three people sat at each table. He saw that the familiar Twelve Little Strongmen were all his deskmates. The current desk-sharing was basically for future teams.

It really is...fate's arrangement!

Suddenly, a quarrel broke out outside the door, and everyone peered curiously towards the door...

"Hey, apologize to her," Naruto clenched his fists, shielding the timid Hinata behind him, and glared at the several ugly and arrogant classmates in front of him.

"No way, you Byakugan monster!" the chubby classmate laughed and made a face at Hinata.

"Damn it!" Naruto cursed angrily and slammed his fist down on the spot.

"Tsk tsk, school bullying, huh?" Lin Chuan clicked his tongue as he watched this scene. He rushed towards Naruto, who was fighting three opponents at once. This was a chance to build goodwill with Naruto and maybe even get some benefits later. He immediately shouted, "Naruto, I'm here to help you..."

bang bang bang-

He punched and kicked the fat man who was laughing the most arrogantly, and pointed at someone and beat him to death. This was the way to break the deadlock in a group fight, and he immediately beat these people until they were crying for their parents.

However, during the chaotic brawl, Choji's potato chips were accidentally knocked over. Choji instantly turned red with anger and joined the fray.

"Hey, Choji," Nara Shikamaru was right next to Choji and tried to reach out and grab him, but his small body couldn't move Choji and was dragged into the melee by Choji.

The five-person brawl quickly escalated into a seven-person brawl, leaving Hinata extremely worried. The brawl only stopped when Iruka-sensei appeared and gave each of them a sharp tap on the head, leaving a large pink bump.

Thump, thump, thump—

"Stop it, all of you! Everyone who's fighting, get out there and stand in the hallway!" Iruka's face was contorted with rage; he wished he could give these mischievous guys a massage with his ninjutsu.

"Hey," the few people who were fighting were a little excited to hear that they didn't have to go to class. They were secretly delighted and their boos were a few decibels higher.

"What?!" Iruka's fists were already hard, and he really wanted to give these kids a massage on the bottom, but he couldn't. He could only unleash the ultimate teacher's move, roaring fiercely, "Call all your parents after school..."

"Tsk tsk, I never expected this. He's already thirty years old, and he still has to call his parents." Lin Chuan sat cross-legged on the side of the corridor and began his daily training, starting with refining chakra.

As we all know, chakra is formed by the fusion of physical energy and mental energy. Every ordinary ninja has a limit to the amount of chakra they can hold, and this is what we call ninja talent.

A person's comprehension and intelligence can be considered a kind of talent for ninjas, since they learn things relatively quickly.

An ordinary person without any bloodline—not the Senju, not the Uchiha, and certainly not the Uzumaki clan—has a chakra limit of only Chunin level. No matter how much you train, your chakra reservoir will only hold the amount of Chunin. Anyone who can have the chakra of a Jonin is either exceptionally gifted or related to the Otsutsuki clan.

Bloodline talent determines the upper limit, while personal training determines the lower limit. There are ways to increase chakra reserves, as far as he knows, such as Orochimaru's cursed seal, training in taijutsu like the Eight Gates, training in sage techniques, and borrowing chakra from tailed beasts...

Of course, there are other unorthodox cultivation paths, such as fusing with Hashirama's cells, fusing with other bloodline limits, or starting over by drawing a new card and getting a good bloodline talent...

As for Tsunade's Hundred Healings Seal, this technique doesn't actually increase chakra, but rather stores chakra that isn't usually used, to be used when needed. After using it up, it needs to be accumulated again, and it's very difficult to learn.

His ordinary body's chakra limit is only at the Chunin level. His original mother was an ordinary person, and Old Deng was a cheap Chunin. With such a drop rate and such configuration, it's already quite good that he has Chunin talent.

In addition, he was only average in terms of talent in ninjutsu, taijutsu, and genjutsu. He did not have the ability of the Uchiha to learn ninjutsu after demonstrating it once. He could only rely on accumulated practice to form muscle memory and thus embark on his ninja path.

As for advanced ninjutsu like summoning techniques, sage techniques, sealing techniques, family secret techniques, bloodline limits, Flying Thunder God Technique, and Rasengan, those are far too early for him...

Don't ask why he didn't learn the Rasengan. Even though the Rasengan is the easiest to learn, and the learning steps have been demonstrated in the anime, the Rasengan is still an A-rank ninjutsu, and he simply can't unleash it with his current chakra reserves.

Even if you can barely release a Rasengan once, all your chakra will be drained, and without chakra, you'll die. So there's no point in releasing the Rasengan.

As everyone knows, the prerequisite for becoming stronger in the ninja world is to be strong...

Cough, no, it should be that he was related to the Otsutsuki family, but he was too unlucky and couldn't get into a family with good talent. He always started as a commoner ninja family. What could he do...?

Blame the developers for secretly changing the drop rate; if you can't get an SSR, blame the developers...

……

"Hey, Lin Chuan, what are you doing sitting there? Want some Choji's potato chips?" Naruto gently nudged Lin Chuan's shoulder when he saw Lin Chuan with his eyes closed and not saying anything. Choji was offering them potato chips.

"I'm refining chakra," Lin Chuan said without opening his eyes. He had been refining chakra ever since he transmigrated, and he had set a goal for himself to squeeze out the chakra limit of this body before graduation.

In other words, a person's chakra level at age twelve must reach that of a Chunin to be qualified to compete with these monsters in the Chunin Exams. Therefore, they must train their body even harder.

Refining chakra is to gain the ability to perform "ninjutsu," which is a prerequisite for becoming a ninja to participate in battles and carry out missions.

To put it simply, the speed at which a ninja refines chakra determines the speed at which they can unleash ninjutsu. If you're slow at one step, you'll be slow at every step. The speed at which mental and physical energy merges with chakra, and the proficiency in unleashing ninjutsu, will all fall short. If everyone else is already unleashing ninjutsu while you're still refining chakra and forming hand seals, then it's ridiculous.

In the first part of Naruto, a Jonin's chakra reserves were at most enough to use six or seven A-rank ninjutsu. The reference point is Hatake Kakashi.

When Kakashi was teaching Sasuke how to use Chidori, he said that with Sasuke's chakra reserves as a Chunin, he could only use the A-rank Lightning Release ninjutsu Chidori twice at most. Using it a third time would cause him to overexert himself and fall unconscious.

Kakashi, due to the burden of the Sharingan, can only use A-rank ninjutsu a maximum of four times a day. Even without the Sharingan, he can only use A-rank ninjutsu six or seven times a day.

Actually, Kakashi's status as a Jonin was weakened in the early stages. The Sharingan, an eye that can never be turned off, has both advantages and disadvantages. It gave Kakashi excellent dynamic vision, but it also made him extremely short on chakra.

This is the chakra level of an ordinary Jonin. Forget about the freakish level of Huang Tu, even Kakashi in the later stages didn't lack chakra. The chakra levels of later Jonin are not considered, while Kage-level ninjas don't lack chakra.

Now that he knew the chakra levels of both Jonin and Chunin, things became simple. He compared his own chakra level with that of his cheap Chunin father.

He calculated that his current chakra level was equivalent to half of an A-rank ninjutsu, which meant he could unleash three C-rank ninjutsu. Don't think that's an exaggeration; Sasuke and Itachi were already able to unleash the Great Fireball Jutsu at this point, and Itachi learned it even earlier. He was pushing his body to its limits, aiming to match Sasuke's early performance.

The Uchiha clan was wiped out when Sasuke was seven years old. They started attending the Ninja Academy at the age of six. With only one year left until the night of the Uchiha clan's massacre, he made no preparations.

After all, he can go back and start over, so time isn't that tight. He can just slowly grow stronger. The Uchiha clan massacre has nothing to do with him; it's not something a child like him can get involved in.

Returning to the topic of chakra reserves, six C-rank ninjutsu can be exchanged for one A-rank ninjutsu. His goal is to have enough chakra to release two A-rank ninjutsu by the time he graduates, which would just be the level of a Chunin.

The limit for Chunin is only three A-rank ninjutsu. Even when Sasuke was using the Cursed Seal, he was still knocked unconscious by three Chidori attacks, which shows where the limit for Chunin is.

After hundreds of opening the door and drawing lots, he has come into contact with chakra more than ten times. Each time, he started refining chakra at the age of three. It took him three years to raise his chakra level to half an A-rank ninjutsu.

He has six years of schooling ahead of him, which will allow him to improve his chakra level by at least one A-rank ninjutsu. With his body growing and constantly being pushed to its limits, it's possible for him to reach the chakra level of two A-rank ninjutsu.

Even at the very least, there's an A-rank ninjutsu, plus half the chakra of an A-rank ninjutsu, enough to use the D-rank ninjutsu Body Flicker Technique more than ten times. If you can't win, can't you just run away? That's enough to save your life.