Lin Zeqiu had complex feelings about his sister.

Before Lin Zhixia started elementary school, she would often say things at home that completely disregarded his feelings.

For instance, Lin Zhixia had once asked him: “Brother, this book describes the quantum Hall effect. As the magnetic field strength increases, how do you think the conductance of the edge Landau levels in this sample will change?”

Lin Zeqiu’s response was just one word: “Scram.”

Another example: Lin Zhixia had probed: “Brother, cytoplasmic inheritance is maternal inheritance, and mitochondrial DNA all comes from the mother. Brother, our parents are the same, so why don’t you and I look alike at all? Let’s read ‘Analysis of Cellular Genetics’ together!”

Lin Zeqiu’s response was just two words: “Shut up.”

And Lin Zeqiu’s most memorable incident—one day, their parents had a rare day off and took the siblings to the park for an outing. At that time, six-year-old Lin Zhixia clung to her brother, chattering non-stop: “Brother, have you studied the origin of species? Do you know if there are gaps in the evolutionary history of ancient humans? Do you believe all human races come from Africa? Do you think Darwin’s Theory of Evolution can explain the development of ancient apes? Brother, almost all mammals have fur, yet sweat glands are among the most developed organs in humans. This determines that human endurance is stronger than other mammals. Brother, do you know why this is?”

Lin Zeqiu broke down on the spot: “Don’t bother me!”

He strode away, running far away. Lin Zhixia was still chasing him from behind, like a demon king from hell. No matter how far Lin Zeqiu ran, he couldn’t escape Lin Zhixia’s pursuit.

He shouted at her: “Stay away from me!”

Then, he was immediately criticized by his parents. His parents reprimanded him for having too much of a temper and being too harsh with his sister. His good mood for the outing was completely gone, his enthusiasm hit rock bottom, and the excursion became completely joyless.

Their parents were biased. Especially their mother, who had completely different attitudes toward her son and daughter. For Lin Zhixia, her mother would do many things.

For example, Lin Zhixia particularly liked going to the Provincial Library. Regardless of how business was at the store, mother would always make time every week to take her to the library to borrow and find books.

Their parents tried their best to nurture Lin Zhixia. They made sacrifices in terms of time and money.

To avoid delaying the store’s opening, mother would generally go to the wholesale market at four in the morning to purchase goods. Father would help count the merchandise and check the accounts. The household chores, including washing dishes, sweeping, mopping, and doing laundry, were often assigned to Lin Zeqiu.

While Lin Zhixia didn’t have to do anything.

When Lin Zeqiu complained, his mother would tell him, “Your sister is three years younger than you, can’t you give in to her a little?”

He could only pretend not to care. Over time, he grew accustomed to it.

Most terrifying of all, after Lin Zeqiu turned 10, Lin Zhixia became eager to tutor him in his studies.

While tutoring, she would confusedly ask: “Brother, does this problem stump you? Brother, do you not understand?”

In Lin Zeqiu’s nightmares, there would occasionally be Lin Zhixia’s unbridled and arrogant questioning.

However, tonight, things were a bit different. Apart from explaining the solution method, Lin Zhixia didn’t say anything else to Lin Zeqiu.

She sat quietly in her chair, calmly watching Lin Zeqiu write. Her cheeks had a rosy glow, and her eyes held the morning star. She was a kind-hearted, beautiful little angel.

The bonus question on the math test paper had been perfectly solved by Lin Zeqiu.

Tomorrow morning, when the homeroom teacher corrected the test papers in class, Lin Zeqiu would likely be the only one in the class who could solve this problem.

Without a doubt, Lin Zeqiu had preserved the dignity of being the math representative. He glanced sideways at his sister, and although he didn’t explicitly say it, he was somewhat moved in his heart.

Lin Zhixia looked back at him.

Lin Zeqiu clutched the test paper and said to his sister: “You’re usually very annoying. But when you’re not annoying, you’re quite capable.”

Lin Zhixia nodded and frankly told him: “Brother, when you encounter problems you don’t understand, don’t just struggle on your own. If you can’t figure it out, come find me. Whether it’s middle school or high school problems, ordinary difficulty or competition level, I can usually solve them. My deskmate gave me several workbooks for physics competitions, and I discovered patterns in the questions from previous years. Brother, as long as you want to know, I’ll tell you all my thoughts! I can treat you as my student…”

“Enough,” Lin Zeqiu closed the test paper, trying to maintain a gentle tone, “you can get out now, the farther the better, Lin Zhixia.”

“You’re being mean to me again!” Lin Zhixia said indignantly, “I’m leaving right now!”

Lin Zeqiu chuckled: “Go and don’t come back!”

Lin Zhixia ran out of his room.

He took a deep breath and worked hard to complete his English and Chinese assignments.

Lin Zeqiu organized his backpack, tidied his desk, went to the bathroom to brush his teeth and wash his face, and finally collapsed onto his bed, exhausted in body and mind.

Don’t dream about Lin Zhixia—this was his only wish before falling asleep tonight.

*

The next morning, Lin Zeqiu went to school as usual.

As he wished, the first class was mathematics.

As a diligent and responsible math representative, Lin Zeqiu had already collected all the homework from the class. Subsequently, at the homeroom teacher’s indication, Lin Zeqiu distributed the papers to the group leaders of each team.

Every student in the class had a test paper from another student.

“Students,” the homeroom teacher knocked on the blackboard, “correct the test papers with me and grade your classmates’ papers. You should write down the correct solutions in your notebooks. Don’t let my teaching go to waste. When you encounter the same problems next time, you shouldn’t make the same mistakes, alright?”

The homeroom teacher started with the first multiple-choice question.

Lin Zeqiu, holding a red pen, involuntarily looked forward to the bonus question.

He occasionally glanced at his watch.

He waited for thirty-nine minutes.

A class was forty-five minutes, with just six minutes left before the end.

By this time, the entire test paper had been answered, with only the final bonus question remaining.

The homeroom teacher coughed and asked the whole class: “This problem is a bit difficult, falling within the scope of middle school mathematics competitions. Did anyone in our class manage to solve it?”

Lin Zeqiu didn’t waste a second and immediately raised his hand.

The homeroom teacher’s eyes brightened: “Good! Lin Zeqiu! My math representative! Come up to the blackboard and explain it to everyone.”

Lin Zeqiu stood up in the spotlight of everyone’s attention.

He didn’t even notice that “come up to the blackboard” was a grammatically awkward phrase.

Even if he had noticed, what could he do? The homeroom teacher was a math teacher. Students shouldn’t be overly critical of his language proficiency.

Lin Zeqiu walked to the podium, picked up the chalk, and summarized the solution approach for everyone.

Many classmates in the class let out enlightened “Oh Oh-Oh-Oh-Ah” sounds.

The homeroom teacher also praised Lin Zeqiu’s method.

The homeroom teacher said, “Lin Zeqiu flexibly applied mathematical induction. When n is greater than or equal to 2, the formula Lin Zeqiu listed is very concise and has a bit of a trick to it. You should all learn from him.”

This trick wasn’t Lin Zeqiu’s trick.

It was Lin Zhixia’s trick.

At this moment, Lin Zeqiu suddenly thought of his sister.

A terrifying hypothesis popped into his mind—what if his sister suddenly skipped grades and started middle school next year, would she crush all the middle school students in the entire grade?

If this hypothesis came true, when Lin Zeqiu walked around school, he would be pointed at and discussed.

Classmates might say: Look! That’s Lin Zhixia’s brother! Lin Zhixia probably often tutors her brother with homework!

Lin Zeqiu shuddered, with cold sweat seeping down his back.

He had to divert his attention and force himself to think about other issues… for instance, his sister had to pay 72 yuan for the hepatitis B vaccine today, had she paid it smoothly? Was she still afraid of shots?

Lin Zeqiu’s concerns weren’t excessive.

Lin Zhixia was sitting on pins and needles at school.

After the bell rang for the end of the first class, the deputy class monitor of fourth grade (1), Tang Leqin, approached Lin Zhixia and asked: “Lin Zhixia, are you getting the hepatitis B vaccine?”

Lin Zhixia silently took out a handkerchief. She untied the knot on the handkerchief, and the 72 yuan in coins and bills lay intact on the table.

Tang Leqin collected the money, noted down Lin Zhixia’s name, and then asked: “Lin Zhixia, you don’t look well?”

Jiang Yubai heard Tang Leqin’s words and turned his head to observe Lin Zhixia. He asked: “Lin Zhixia, are you feeling unwell?”

“No,” Lin Zhixia replied, “I’m… just fine.”

She was deeply delving into her thoughts.

Why fear shots?

Everything has a cause, and causes have effects.

Lin Zhixia believed that her fear of hospitals stemmed from a kind of uncontrollable uncertainty.

When she went to the hospital, she would always see elderly people in wheelchairs, patients with mobile IV drips, and doctors with hurried expressions and quick footsteps. The hospital was a convergence point of life and death, a center of contrast between health and illness, making her think of many philosophical questions that couldn’t be explained.

Liezi once said: “Die in ten years, die in a hundred years. Just focus on the present life, why worry about after death?” The meaning of this statement is—don’t overthink, live well while alive.

The German philosopher Heidegger had also proposed a philosophical concept called “Dasein.”

The word “Dasein” in German means “existence.” Heidegger’s theory can be summarized as “being toward death,” which translates to “living toward death” in Chinese.

Living toward death!

According to Heidegger’s theory, although everyone is a living organism, only by being aware of one’s existence, aware that one will eventually die, and continuously growing and expanding one’s horizons in the process of moving toward death, can one truly be considered “Dasein” in the real sense.

This was the principle, and Lin Zhixia was striving to comprehend the Zen wisdom.

Once she had an epiphany, she could overcome her fear!

Defeat herself!

Become the “superman” Nietzsche spoke of!

Become the “Dasein” Heidegger referred to!

Yes, that’s it.

Lin Zhixia adjusted her mindset, then reopened her notebook to record today’s “Human Observation Diary.”

She wrote: Today I will observe myself. My research question is—is Lin Zhixia truly a person of weak will?

Jiang Yubai saw the entire line that Lin Zhixia wrote.

Jiang Yubai asked her: “Weak will? What are you afraid of?”

Lin Zhixia hesitated for a moment. She originally didn’t want to tell the truth, because she hadn’t shed the idol burden brought by the “Exploring the Universe” comic series. But obviously, Jiang Yubai was concerned about her. She should honestly respond to the concern from a good friend.

She said softly: “I’m afraid of shots.”

Jiang Yubai asked: “Why?”

His tone was particularly caring, and Lin Zhixia couldn’t help but tell him the truth: “Because shots hurt. I’m afraid of pain. Are you going to mock me now?”

Jiang Yubai turned around, faced her, and seriously said to her: “That’s okay, everyone has something they’re afraid of.”

Lin Zhixia also faced him and asked: “Jiang Yubai, what are you afraid of?”

“I’m afraid of dirty things,” Jiang Yubai confessed his flaw, “my room can’t have obvious dust. The bed sheets, duvet covers, and pillowcases must be changed daily.”

Lin Zhixia nodded: “You’re very particular.”

Jiang Yubai shook his head: “Not particular, I’m just nitpicking.”

Lin Zhixia praised him: “You’re so modest.”

Jiang Yubai casually said: “Not as much as you.”

Lin Zhixia tugged at his sleeve: “Do you think you’re not as good as me?”

The friendly relationship of “mutual praise” that she and Jiang Yubai had established was shattered in that instant.

Jiang Yubai sat up straight again, smoothed his cuffs, and his self-esteem seemed to ache faintly. But he still patiently comforted her: “Don’t be afraid, the vaccine won’t affect your life.”

“But do you know?” Lin Zhixia informed him, “The essence of the hepatitis B vaccine is inactivated virus. After the injection, I might get a fever.”

Jiang Yubai was unconcerned: “You might get a fever, but it’s not certain that you will.”

Lin Zhixia steadied herself and explained: “The famous mathematical inference—Murphy’s Law tells us that if something can go wrong, it will eventually go wrong. When you choose any set for integration to calculate measure…”

“Please speak like a normal person.” Jiang Yubai made his request.

Lin Zhixia complied readily: “I mean, whatever you fear is what will happen.”

“No,” Jiang Yubai resolutely comforted her, “be more optimistic.”

But Lin Zhixia said: “I’ve always been optimistic!”

*

Lin Zhixia maintained an optimistic attitude and passed the next few weeks smoothly.

In early December, the Experimental Elementary School organized a diagnostic test.

Ordinary students would generally read textbooks, study hard, and review notes before an exam.

Lin Zhixia had a certain degree of similarity with ordinary students—she would also read a lot of books before an exam.

But she didn’t read textbooks.

For instance, before this fourth-grade first semester diagnostic test, Lin Zhixia quickly browsed through “Unified Theory and Supersymmetry,” “New Edition of Quantum Computing,” and “Beyond Space-Time” at the library.

When she was in the exam room, rapidly completing the test paper, she would recall the contents of those library books in her mind.

She organized her thoughts in her head, repeatedly deriving mathematical equations, essentially arranging another test for herself.

At this moment, the entire exam room was unusually quiet. The invigilating teacher sat at the edge of the podium, never disturbing the students.

Lin Zhixia glanced up and happened to see Jiang Yubai sitting diagonally in front of her.

Jiang Yubai’s posture was very upright. He held his pen properly and wrote diligently.

Lin Zhixia stared at his back, lost in thought, and without realizing it, the school broadcast announced the instruction “Teachers collect papers, the exam is over.”

Lin Zhixia stretched lazily.

The invigilating teacher was a young male teacher. He walked up to Lin Zhixia, collected her test paper, his gaze passing over the English composition on the paper, and although he was somewhat surprised, he didn’t say anything.

“The exam is over!” Lin Zhixia happily announced.

She jumped to Jiang Yubai’s desk: “Jiang Yubai, how did you do on the exam?”

Lin Zhixia wanted to know what kind of mindset Jiang Yubai had after completing a major exam. This way, her “Human Observation Diary” would have new material.

Jiang Yubai appeared confident. He smiled faintly and said: “I did okay.”

Ding Yan, passing by, heard this and immediately became alert: “Really?”

Jiang Yubai unscrewed his water bottle and took a sip of Fiji mineral water. Although he didn’t reveal a hint in his words, in his heart, he felt that this exam was solid. He would surely be the top student in the class.

Although Lin Zhixia was exceptionally gifted, she might not be familiar with the techniques of test-oriented education.

While he, Jiang Yubai, after four months of intensive training with a home tutor, could recite the solution methods for the “Hua Luogeng Gold Cup Elementary School Mathematics Competition” in his sleep.

This exam, both the math and English papers, was very difficult, with the question-setters taking tricky and peculiar angles, living up to the experimental teaching materials of the Provincial Experimental Elementary School.

Seven minutes into the exam, Jiang Yubai had looked back once. He discovered that Lin Zhixia was daydreaming.

With ten minutes left before the end of the exam, Jiang Yubai looked back again. He found that Lin Zhixia was still daydreaming. She hadn’t changed her posture at all.

Why was she so motionless?

She might be thinking about physics.

It was this fleeting glimpse that restored Jiang Yubai’s confidence.

Lin Zhixia was indeed intelligent. She was a genius among geniuses. But she would also get distracted. She would also be careless and absent-minded.

At this moment, Jiang Yubai stood up from his seat. His dignity also stood up from the ground. He asked Lin Zhixia: “Do you care about grade rankings?”

Lin Zhixia answered casually: “Exam grade rankings? I don’t care. I’m always first in the grade. How high my total score is depends on my mood.”

Lin Zhixia was too proud.

As the saying goes, “Pride leads to defeat,” and it’s not without reason.

According to Jiang Yubai’s estimation, Lin Zhixia had been distracted for quite a while. She might not have completed the test paper. Under normal circumstances, even if she had finished, she should have taken time to check all the questions.

No one is perfect, there’s always someone better, and even the strongest opponent has moments of error.

So, Jiang Yubai mustered his courage and issued a challenge to Lin Zhixia: “Lin Zhixia, you used to get first place because I hadn’t transferred here yet.”

As soon as he finished speaking, several nearby classmates stared at him.

Lin Zhixia stared into his eyes: “Are you saying that this time, you did very well on the exam, you can surpass me, and become first in the grade?”

Ding Yan grabbed Jiang Yubai’s sleeve, silently signaling him not to speak carelessly, not to bring humiliation and trouble upon himself.

Ding Yan had witnessed Lin Zhixia’s extraordinary intelligence.

He believed that no student in the entire school could be smarter than Lin Zhixia.

As Jiang Yubai’s good friend, Ding Yan would never stand by and watch Jiang Yubai be humiliated in front of Lin Zhixia.

Although Jiang Yubai considered Lin Zhixia a competitor and dreamed of hearing Lin Zhixia praise him as impressive, everyone knew that was an impossible event.

Ding Yan couldn’t help but earnestly advise: “Jiang Yubai, let it go, be more open-minded.”

How interesting.

What did “be more open-minded” mean?

Jiang Yubai had his persistence.

He brushed aside Ding Yan’s hand, moved forward bravely, fearlessly. Facing Lin Zhixia, he said with neither arrogance nor servility: “Lin Zhixia, I can surpass you. This time, I should be first in the grade.”

Lin Zhixia was stunned for a moment before saying: “Jiang Yubai, we’ve been deskmates for four months, and you still don’t have a comprehensive understanding of me. Let’s make a bet.”

As she spoke, she walked toward the classroom door.

All the students’ backpacks were placed along the wall in the corridor outside the classroom.

The plastic floor was stained with footprints. Jiang Yubai picked up his backpack but didn’t put it on his back. He held the backpack strap with one hand, following Lin Zhixia’s footsteps, and asked her: “Lin Zhixia, what bet do you want to make?”

Lin Zhixia stopped.

Today the sun was bright, and the ceramic tiles of the teaching building gleamed with reflection.

She patted a ceramic tile and said straightforwardly: “Jiang Yubai, if you’re first in the grade, I’ll call you Teacher Jiang. If I’m first in the grade, you’ll call me Teacher Lin, as a sign of respect.”

Jiang Yubai took a step back.

He didn’t immediately agree.

Jiang Yubai reflected on his recent words and actions. He believed his behavior wasn’t polite enough. Even when dealing with a competitor, he should show due respect and carefully evaluate the competitor’s proposal.

Should he accept Lin Zhixia’s bet?

Jiang Yubai had done extremely well on this exam.

His math and English should both be perfect scores. He was also fully confident about Chinese.

For Jiang Yubai with three perfect scores, the worst outcome would simply be tying with Lin Zhixia for first in the grade.

He accepted Lin Zhixia’s bet: “Alright.”

He also said: “Don’t cry when you lose.”

“I won’t cry,” Lin Zhixia said, “I’m very strong.”

Jiang Yubai reminded her: “Next Monday, all students will start receiving the hepatitis B vaccine…” His voice gradually lowered, sounding very gentle: “Don’t be afraid.”

Lin Zhixia shouldered her backpack and ran out of the corridor.

*

This weekend, Lin Zhixia didn’t go to the library.

She made an excuse saying she was tired and wanted to rest, causing both her parents to show surprised expressions.

But her brother saw through her with one glance: “Are you still worried about getting the vaccine?”

Lin Zhixia hugged her plush penguin toy tightly: “I’m not.”

Lin Zeqiu said: “Whenever you’re scared, you hug this penguin.” He tilted his head slightly: “The penguin looks silly.”

He was wearing athletic clothes, had changed into sports shoes, and picked up a basketball from the floor, ready to go out.

Lin Zeqiu hadn’t gone out to play for an entire month.

It was rather distressing, but last month, the family business was particularly busy, and Lin Zeqiu had to clean the house every day, in addition to taking his academics seriously. But today! He had finally come alive! He couldn’t wait to see his classmates and play an invigorating game of basketball with them.

Lin Zhixia unexpectedly asked him: “When you go play basketball, can you take me along?”

“Lin Zhixia,” Lin Zeqiu questioned her, “do you know how to play basketball?”

Lin Zhixia reasoned: “I don’t. That’s why I want to observe you all.”

Lin Zeqiu flatly refused: “My group of classmates has never played with girls. If you come to the basketball court, we’ll all feel uncomfortable.”

“Then can you stay home and play cat’s cradle with me?” Lin Zhixia immediately pulled out a string.

Lin Zeqiu pushed her hand away: “Don’t block my way, I haven’t touched a basketball in ages.”

“Brother…” Lin Zhixia lowered her head, “Do you find me annoying? Before, I didn’t have a deskmate at school and didn’t dare talk to others, I could only find girls to play cat’s cradle during breaks. When they played jump rope, I was always the person holding the rope. Now brother doesn’t want to play cat’s cradle with me either.”

When Lin Zeqiu heard her mention “I didn’t have a deskmate at school and didn’t dare talk to others,” his movements became much more hesitant.

He stood in front of the security door, took a step forward, then retracted his leg, even though his classmates were still waiting for him at the basketball court.

He looked at Lin Zhixia, who still had her head lowered.

Lin Zeqiu felt a twinge in his heart and said gently: “Forget it, I’ll play cat’s cradle with you.”

“What about your classmates?” Lin Zhixia immediately raised her head.

Lin Zeqiu replied nonchalantly: “Why do you care about them? It’s not the first time I’ve stood them up. They’re used to it by now.”