Lin Zhixia was full of energy and ambition. Holding the landline receiver, she declared with determination: “Jiang Yubai, I’ll bring back the gold medal from this competition for you to play with.”

Jiang Yubai went along with her: “I’ve indeed never played with a National Math Olympiad gold medal before.”

“When I return,” Lin Zhixia promised him, “I’ll treat you to a meal in the school cafeteria.”

Jiang Yubai didn’t particularly like the school cafeteria. But he was unwilling to admit that he was a picky eater. Instead, he invited Lin Zhixia: “I’ll have you come to my home for a meal.”

Lin Zhixia suddenly remembered the “museum pass” Jiang Yubai had given her. She asked with great anticipation: “When can I visit your home?”

Jiang Yubai answered: “Whenever you’re free.”

Lin Zhixia jumped in place: “Great, Jiang Yubai, see you next month.”

Jiang Yubai responded: “See you next month.”

Before ending the call, Lin Zhixia added casually: “Tomorrow at six in the evening, I’ll call you promptly, okay?”

“Okay,” Jiang Yubai concisely agreed.

The atmosphere at the dinner table was quite still. Jiang Yubai put his phone into his pocket and picked up a grilled eel roll with his chopsticks. The eel roll contained cucumber, eel, and avocado, wrapped in a layer of seaweed, with white sesame seeds on the surface. He thought Lin Zhixia would probably like this dish. He was already secretly planning future lunches. He hoped Lin Zhixia would enjoy herself at his home.

His uncle suddenly asked him: “Jiang Yubai, did you just have a call with Lin Zhixia?”

Jiang Yubai admitted: “Yes.”

He had waited for almost two days before finally receiving Lin Zhixia’s call. He had pressed the answer button without hesitation, almost forgetting that his parents and uncle were still beside him. He carefully weighed the conversation they had just had, believing that his words hadn’t been inappropriate and met his parents’ consistent expectations.

His mother smiled and said: “You and Lin Zhixia get along very well.”

His uncle raised his clear wine glass: “Sister-in-law, let me tell you, I’ve met Lin Zhixia. Young Lin Zhixia has an IQ of 174; she’s truly not an ordinary girl. Our little Jiang’s friendship with her… It’s like my relationship with young masters in the classical music world—we maintain a pure and unblemished relationship, one that encourages mutual growth. Little Jiang’s willingness to humbly learn from others might have been learned from me.”

His father questioned: “Is that so?”

His uncle put down his wine glass and immediately changed his tune: “More likely, it’s something Little Jiang realized on his own.”

His father leaned slightly against the chair back, quietly looking at Jiang Yubai. After a moment, his father said gently, “You and Lin Zhixia are good friends. We’re happy to see you getting along well with your classmates…”

His father’s fingers encircled the rim of his wine glass, and his words stopped halfway—this was quite rare. He usually educated his son with clear logic and in an orderly manner. Tonight, however, he glanced at his wife.

Jiang Yubai’s mother took on this responsibility. She wiped the corner of her mouth with a napkin and subtly reminded him: “Jiang Yubai, you’re eleven years old. In a few months, you’ll be twelve, a young man. When you’re friends with a little girl, you must understand that the two of you are of different genders. You must respect her and grasp the appropriate boundaries and limits.”

Jiang Yubai nodded once.

His uncle’s fingertips lightly tapped the wine glass: “Yes, maintain boundaries, Little Jiang.”

Jiang Yubai readily replied: “No problem.”

“That’s good,” his mother said, “Dad and Mom both trust you.”

The advice from his parents and uncle awakened Jiang Yubai’s gender awareness. Although he had always held himself to “a young man’s standards” since childhood, he indeed often overlooked “the boundary issues between boys and girls.” Fortunately, he and Lin Zhixia had maintained a profound friendship, respecting and encouraging each other, never offending one another—he had completely forgotten how, at nine years old, his self-esteem had been demolished by Lin Zhixia.

That night at eight-thirty, Jiang Yubai went to sleep with a calm mind.

At the same time, Lin Zhixia turned off the lights and went to bed.

Lin Zhixia held her little penguin with her left hand, pulled back the blanket with her right, and lay down in the soft bed. She silently repeated Jiang Yubai’s words—the universe is black, but she wasn’t afraid of the universe. She believed her fear came from the unknown. For example, “dark matter” is a type of invisible matter in astrophysical theory, widely distributed throughout space. If “dark matter” truly existed and Lin Zhixia could see it, then the universe, in her eyes, should be another kind of grand and dazzling spectacle.

Darkness and light are both relative concepts. As long as there was light in Lin Zhixia’s heart, even the pitch-black night would be bright.

Lin Zhixia no longer retreated or felt timid. She lay flat on the bed, exposing her entire face, just like sleeping at home, and slept peacefully until the next morning.

At eight o’clock in the morning, the National Mathematics Olympiad officially began.

The National Mathematics Olympiad had another name, called the “National Middle School Students Mathematics Winter Camp.”

Lin Zhixia had proudly announced to her parents that she was participating in the National Mathematics Olympiad. But in front of others, she modestly stated that she had signed up for a winter camp.

The winter camp problems were very high-level. The first question was an algebra problem: given a non-decreasing sequence of positive integers, with a subsequence containing n distinct positive integers, prove the lower bound of the sum formula for the general term of the sequence. Lin Zhixia proved another proposition, then narrowed the scope, applied it to the summation formula specified in the problem, and quickly solved it.

Next, she encountered problems in plane geometry and combinatorics.

Lin Zhixia didn’t waste a single minute, writing her thought process directly on the answer sheet.

The so-called “math competition” was really just solving problems silently in an examination room. The International Olympic Mathematics Competition was solving problems together with contestants from all over the world. There was no essential difference between competitions and exams, so Lin Zhixia felt no pressure.

The mathematics competition was divided into two days, with three problems each day, 21 points per problem. After finishing her exam paper, Lin Zhixia’s thoughts were sparked by the problems. She sat in the classroom, her mind full of Hua Luogeng’s “Theory of Prime Number Stacking.”

When she walked out of the examination room and reunited with the provincial team’s head teacher, the teacher asked her how the exam went, and she unconsciously blurted out: “Abelian groups and commutative semigroups.”

The teacher was stunned.

The other students on the provincial team were also stunned.

Lin Zhixia hurriedly said: “I did pretty well.”

Most of the contestants in the provincial team were boys, with girls making up only a small portion. Looking across the entire winter camp, the number of girls was not predominant. On the international Olympic battlefields over the years, the national teams of various countries were mainly composed of male contestants. Perhaps for this reason, Lin Zhixia received a lot of attention at the competition venue.

Oh, and there was another reason—she was too young.

She cautiously expressed her opinion: “The questions on this test were excellent, especially that combinatorics problem. The construction was clever, starting from the pigeonhole principle, not beyond the curriculum, yet it exercised the mind.”

A boy beside her, however, said: “There’s nothing much to say about that problem.”

Lin Zhixia looked up at him.

This boy was a senior from the high school competition class of Provincial No. 1 Middle School, named Guan Tong.

Senior Guan Tong was seventeen years old, a high school senior who had already secured admission to university without taking the entrance exam. He was considered an outstanding student in the high school competition class. His goal was to win a gold medal at the International Mathematics Olympiad, and this year was his last chance to seize the championship.

Lin Zhixia felt there was a generation gap between her and Guan Tong. Guan Tong often contradicted her viewpoints—no matter what opinion she expressed, Guan Tong would immediately offer a different perspective.

In contrast, another senior student named Luo Ying in the provincial team had a much better attitude than Guan Tong.

Luo Ying was a senior from the second-year high school competition class at Provincial No. 1 Middle School. At the 2005 high school club orientation, Lin Zhixia had crossed paths with Luo Ying. She remembered that at that time, Senior Luo Ying was still in the advanced class of the high school division. Later, the senior transferred to the competition class. It was said that the senior was extremely hardworking, waking up early and sleeping late, working diligently for a full year and a half before firmly establishing herself in the competition class.

Lin Zhixia especially admired such people. She was full of respect for Senior Luo Ying and often followed behind Luo Ying, happily calling her: “Senior, Senior.”

Luo Ying was also very protective of Lin Zhixia.

Hearing Guan Tong’s words, Luo Ying immediately retorted: “Nothing much to say about the problem? Can you give me a similar problem?”

Guan Tong laughed with a “ha ha.” He awkwardly wiped his face, his gaze lingering on Luo Ying’s face. In the bitter cold of late January, with the biting wind, he and Luo Ying looked at each other for ten seconds, and his chest began to produce a thin layer of sweat. As the sweat corroded his chest, he stood with his head high and chest out, saying: “Luo Ying…”

Luo Ying pretended not to hear him.

In the senior grade, Guan Tong was considered a prominent figure. He was tall and thin, with proper features, excellent grades, and had secured university admission, with one foot already in the mathematics department of a top university. How bright and clear his future was!

However, whenever he tried to talk to Luo Ying, she always ignored him.

Luo Ying only said to Lin Zhixia: “Let’s go to the fruit shop at the hotel entrance to buy strawberries.”

Lin Zhixia’s eyes brightened: “Strawberries? Yes, yes!” She circled Luo Ying: “Senior, do you like strawberries?”

Luo Ying said: “I like watermelon.”

“Oh yes, I like watermelon too,” Lin Zhixia replied.

Their voices gradually faded away.

The corridor was empty.

*

Two days later, the winter camp competition results were announced. Just as Lin Zhixia had declared, she won a gold medal in this competition and had the opportunity to enter the national training team to participate in international mathematics competitions.

When the news reached Provincial No. 1 Middle School, the entire school was in an uproar.

Local reporters waited at the school gate, seeking to interview Lin Zhixia. A newspaper called “Morning Daily” had even drafted a headline titled “A Smart Girl’s National Math Olympiad Journey.” They eagerly awaited Lin Zhixia’s response; as soon as she agreed to an interview, the article would immediately be published.

To everyone’s surprise, Lin Zhixia refused all interviews. She said she wasn’t mature enough yet and hadn’t grown to the point where she could face public media alone. The focused attention of the public would multiply her pressure.

The principal of Provincial No. 1 Middle School immediately stepped in, coordinating all media, and the news of Lin Zhixia’s award spread only within the school campus.

Jiang Yubai thought that Lin Zhixia’s decision showed foresight. In any case, she was only twelve years old, and too much outside attention might affect her peaceful life. Moreover, she had already won the National Mathematics Competition gold medal, and gaining admission to university without taking entrance exams was no problem… Just as Jiang Yubai was thinking about this, Lin Zhixia said to him: “Look, this is my gold medal.”

They were in a class meeting at that moment.

Teacher Zhang spent five minutes specifically praising Lin Zhixia. Afterward, Teacher Zhang discussed “class culture building.” He hoped all students would set goals, maintain confidence, and continue to move forward.

After Teacher Zhang finished speaking, the applause in Class 2(17) continued for a long time.

Lin Zhixia moved an inch closer to the edge of her seat and stuffed the gold medal into Jiang Yubai’s hand.

This was the first time Jiang Yubai had touched a National Mathematics Competition gold medal—in this year’s competition, dozens of gold medal winners emerged nationwide, and Lin Zhixia was one of those dozens.

Jiang Yubai looked down at the gold medal: “Very impressive.” He praised Lin Zhixia: “This is something you deserve.”

Lin Zhixia held the ribbon of the gold medal, wrapping it around her wrist. She placed her right hand on the desk and said after a moment: “Jiang Yubai, I might be… very busy this semester.”

Jiang Yubai thought Lin Zhixia was about to go to university. He couldn’t face her departure as calmly as he had when encouraging her to go to the high school division before. He sat silently, his back straight as a bamboo.

He heard Lin Zhixia say softly: “In a couple of days, I’m joining the national training team, and then I’ll probably participate in the 2007 Romanian Mathematics Masters Tournament. At the Romanian Mathematics Masters Tournament at the end of February this year, each country can only send four contestants…”

Jiang Yubai picked up his pen and wrote in his notebook: Lin Zhixia > 2007 Mathematics Masters Tournament.

“What does that mean?” Lin Zhixia asked.

“It means Lin Zhixia will succeed,” Jiang Yubai answered.

Jiang Yubai capped his pen, regaining his usual composure. He said calmly, “Good luck, Lin Zhixia. The international battle has begun, you should…”

“I should charge into battle!” Lin Zhixia proudly announced.

She was radiant with brilliance, seemingly different from a while ago. Jiang Yubai could vaguely sense her growth and transformation. He discussed with her: “You don’t have time to come to my home this month. Next month…”

Lin Zhixia interrupted him again: “Next month I’ll come to your home to play.”