Siheyuan (traditional courtyard house): Starting with the Korean War, returning home to take charge

In early April, an invitation was delivered to He Yuzhu.

The envelope was made of kraft paper and signed "Institute of Metal Research, Chinese Academy of Sciences." When he opened it, he thought it was a document forwarded by the General Staff. But when he took it out, he saw that the heading was handwritten, and the signature was also handwritten: Qian Zhiyuan.

He read the paper twice.

The back includes a six-page list of technical questions. The handwriting is neat, dense, and all handwritten. The first question is: "Regarding the fiber material sample, is its structural integrity after impact in a combat environment superior to that of currently used bulletproof materials?" The second question is: "Is there any measured data on the degree of discharge efficiency degradation of the battery sample in an environment of minus twenty degrees Celsius?" The third, fourth, fifth... By the sixth question, it already involves "whether the material system is theoretically feasible for mass production."

He Yuzhu put the letter down. He took out a cigarette and lit it.

The sunlight streaming in through the window illuminated the handwritten words, making each stroke clear.

He finished his cigarette and picked up the phone.

"Switchboard, connect me—" He paused, then gave a four-digit number.

The phone rang three times. The person on the other end answered.

"Shen Lian".

"Me," He Yuzhu leaned back in his chair, "You revealed my connections?"

Shen Lian remained silent for two seconds.

"I didn't disclose anything," he said. "I only said, 'It was captured from the front lines; the channels are sensitive, so I can't ask further.' You'll have to explain yourself."

He Yuzhu hummed in agreement.

Shen Lian added, "I've looked into Qian Zhiyuan. He studied in the US and worked on materials for eight years before the liberation. His current research institute is working on several projects urgently needed for national defense."

He Yuzhu didn't say anything.

"He's been watching your samples for six months," Shen Lian said. "Let him look at them, let him think about them. But don't let him ask too many questions."

The phone hangs up.

He Yuzhu sat there, looking at the letter on the table and the six-page handwritten list of questions. He took out the last spare sample from the system space—a two-finger-width fragment of Kevlar, its edges still bearing traces of charring from when it was seized. He wrapped it in oil paper and put it in his briefcase.

The special train to Shenyang departed from Beijing Station at 9:00 AM.

He Yuzhu was in a soft sleeper compartment, all alone. Outside the window, fields stretched out before him, the wheat seedlings just turning green, a tender, vibrant hue. Leaning against the window, he flipped through the six-page list of questions again, making notes in the margins with a pencil.

He wrote a few lines, then put the pencil away.

He didn't know how to write it. Those things, when systematically instilled, formed a complete knowledge system, but to express them in language understandable in this era, he had to break them down, reorganize them, and rephrase them. Instead of saying "Kevlar," he'd say "an aromatic polyamide fiber." Instead of saying "lithium-ion battery," he'd say "lithium-based electrolyte system." Instead of saying "energy density," he'd say "can store more electricity for the same weight."

He leaned against the window, going over the words in his mind.

When the train passed Jinzhou, the attendant brought him lunch. The aluminum lunchbox contained braised pork and potatoes, with the rice packed tightly together. After he finished eating, he put the lunchbox on the small table and continued looking out the window.

We've arrived at Shenyang Station at 3 PM.

Qian Zhiyuan came to pick him up at the station in person. He was sixty-two or sixty-three years old, with gray hair, wearing reading glasses, and a faded blue Zhongshan suit. He stood on the platform, holding up a piece of cardboard with the words "Where is Chang" written on it in calligraphy.

He Yuzhu walked over and stood in front of him.

"Director Qian?"

Qian Zhiyuan put down the cardboard and stretched out his hand.

"I have long admired you, Mr. He."

He Yuzhu grasped his hand. The hand was thin, but steady.

The meeting took place in a row of bungalows on the east side of the institute, not far from the laboratory. Inside, there was a long table, a few chairs, and a blackboard on the wall, covered with densely packed chemical formulas and engineering parameters.

Qian Zhiyuan closed the door, offered him a seat, and poured him tea. Then he took a notebook from a drawer, opened it, and pushed it in front of He Yuzhu.

"He Chang, this is the test data we've collected over the past six months."

He Yuzhu looked down. The data was divided into columns, charts, curves, and rows of notes. He only half understood it, but he knew what the curves meant—the performance of those samples was indeed something never seen before in this era.

"Director Qian," he looked up, "there are some questions I might not be able to answer."

Qian Zhiyuan nodded and pushed his reading glasses up a little.

"If you can answer, then answer. If you can't, let's figure it out together."

The exchange lasted for three days.

The first day, he lectured on the impact resistance principles of fiber materials. He spoke slowly, translating modern terminology into the engineering jargon of 1954 as he went. Qian Zhiyuan listened even slower, occasionally interrupting him to jot down notes in his notebook before letting him continue.

Halfway through the conversation, there was a knock at the door. A young man in a grey Lenin suit poked his head in, saw He Yuzhu, paused for a moment, and then withdrew his head. Qian Zhiyuan got up and went out, and the two exchanged a few words outside, their voices very low. He Yuzhu vaguely heard the words "General Hospital," "confidential," and "investigation."

When Qian Zhiyuan returned, his expression was normal; he simply closed the door behind him.

"Continue," he said.

The next day, the lecture covered the electrolyte system of batteries. When he finished, Qian Zhiyuan leaned back in his chair, staring at the diagram on the blackboard for a long time.

"He Chang," he began, "your knowledge is quite extensive."

He Yuzhu paused for a moment as he tidied up his speech notes.

"Some of it was learned from captured documents, and some from battlefield experience."

Qian Zhiyuan nodded and didn't ask any more questions. But He Yuzhu noticed that he made a few more notes in his notebook, then turned back to the previous page and drew a question mark in red pen in the blank space.

That night, He Yuzhu couldn't sleep at the guesthouse. He stood by the window, looking at the few lights on in the direction of the research institute, thinking of the young man in the gray Lenin suit that afternoon, and the few minutes Qian Zhiyuan had been gone. He brought up the system interface, glanced at his points balance, and then closed it again.

On the third day, he discussed the feasibility of mass production of the materials. He laid out the industrialization barriers, equipment requirements, and raw material sources one by one. Halfway through his presentation, Qian Zhiyuan interrupted him.

"Did Director He get all this from the seized documents?"

He Yuzhu looked at him.

"Some were, and some I figured out myself."

Qian Zhiyuan remained silent for a while.

"Okay." He stood up. "That's all for today. I'll treat you to dinner tonight at the research institute cafeteria, braised pork."

The special train back to Beijing departed at night.

He Yuzhu sat alone in the private room, leaning against the window, watching the occasional flash of lights across the dark fields outside. The car swayed slowly, clattering and rattling.

He reached into his briefcase and touched the stack of documents—the ones Qian Zhiyuan had given him before leaving, saying they were copies of his notes from the past three days of discussions, to be taken back to Beijing and "rethinked." He didn't open them, but he knew what was inside.

He brought up the system interface.

Available points: 55,800,000.

He flipped through the redemption list, turned to the technology category, and looked at it page by page.

He stopped when he turned to the third page.

[Improvement plan for basic aluminum alloy heat treatment process. Required points: 500,000.]

He stared at that line of text for a long time.

I clicked it.

[Confirm redemption? ——Yes]

[Redeem successful. Points consumed: 500,000.]

[Currently available points: 55,300,000.]

He took out a stack of papers from the system space, a thick pile, all handwritten—system-generated, but looking handwritten. Traditional Chinese characters, engineering terms from 1954, each parameter marked with "Suggested small-scale test," "Requires verification," and "Compatibility with current processes to be tested."

He placed the stack of papers on the small table, took out a notebook from his briefcase, and began copying.

He copied very slowly, word by word. He finished one page and turned to the next. When he got to the fourth page, the train stopped. At some station, someone on the platform was shouting, but he couldn't make out what they were saying. After a while, the train started moving again.

He continued copying.

By the time he finished copying the last page, the sky outside the window was already beginning to lighten. He closed the notebook, gathered up the stack of papers, leaned back in his chair, and closed his eyes.

The wheat fields of the North China Plain are falling back one by one outside the window.

1954 October.

The third invitation letter for technical exchange was sent to the General Staff.

When He Yuzhu opened the package, he glanced at the signature and froze – a pharmaceutical research institute in Shanghai.

He finished reading the letter and placed it on the table.

The letter stated that they were researching antibiotics used in battlefield first aid and had heard that "Chief He had successfully performed emergency debridement surgery on the battlefield, using special equipment and medicines," and hoped to consult him in person.

He Yuzhu looked at the letter, recalling the night before the ceasefire in the Battle of Jincheng. That mine. The shrapnel in the recruit's leg. The surgical kit he'd redeemed with 20 points. His hands trembled violently, but he completed every step.

He sat there for a long time.

Then he picked up a pen and began to write. He wrote four pages, breaking down the instruments, procedures, and precautions used in the surgical kit into medical language that could be understood in this era.

After writing the last word, he put down his pen and rubbed his wrist.

The system interface was lit up in the corner of his field of vision. He casually flipped to the "Medicine" category, his eyes scanning the rows of entries. One of them made him pause—"Simplified Scheme for Artemisinin Extraction Process".

The description states that it has significant therapeutic effects on specific infectious diseases in hot regions.

He thought of the soldiers who had been carried off the Korean battlefield due to malaria. He thought of a company commander who survived the war but developed a high fever on the way home and died by the time he was taken to a rear hospital.

He thought for a moment, turned the envelope over, and wrote five words in the corner:

"Artemisinin is worth trying."

After finishing writing, he put the letter in the drawer, stood up, and walked to the window.

The leaves of the old locust tree swayed gently in the wind. The June sunlight was so bright that he squinted.

He didn't know what those five words would become. Maybe they would be useful, maybe they wouldn't. Maybe three or five years later, someone would find this letter in an archive and stare blankly at those five words.

Maybe not.

He stood by the window for a while, then turned around, returned to the table, and began working on the next document.