I received a message from Professor Lim Yonghan at KAIST saying the stock trading program I had commissioned was finally complete.
It was a program that, when you input the expected stock price for tomorrow, would calculate the best return based on the current price, trading volume, and market cap.
People often say stocks are just a numbers game, but in reality, making money purely off charts and numbers isn't easy. The world is full of unexpected variables, and even a company that looks solid on paper can crash from a single piece of bad news.
But I was different. With the ability I'd inherited from my grandfather, I could make risk-free moves. As long as I correctly entered the closing price, the stock would always reach that price the next day.
Later, when my capital became too large, I even accounted for how the price might drop during the selling phase by factoring in trading volume.
Still, I had to test all of that in real scenarios to be sure.
Taking advantage of the weekend to get some fresh air, I headed back to KAIST.
The official reason was to confirm the program and settle the remaining balance. But truthfully, I also wanted to use this chance to get closer to Han Kyung-ah, if the program turned out to be good.
"Once I get more money, I'll probably need updates anyway."
The program should suffice for a while, but you never know what the future holds. It's smart to have a talented programmer in your corner.
As I arrived at the KAIST main gate, I spotted Han Kyung-ah waiting. She looked just the same as before—calm and composed.
"Kyung-ah."
"Oh! Hello."
She bowed politely. Her modest and fresh vibe was quite nice.
"Sorry to make you come all the way. I should've gone to you instead..."
"You're busy with your studies."
"And you're busy with work..."
"Then it's mutual. Isn't it the desperate one who digs the well? So how's the program?"
"Let's not talk here—shall we go to the lab?"
"Sounds good."
Professor Lim's lab was quite spacious. He had tried to make the interior cozy with some plants and model kits, but it still had that engineering student gloom.
Each desk had triple monitors, and even the empty ones had computers whirring loudly. The heat from the machines filled the room.
"Kyung-ah, you're here? Ah, hello."
A disheveled man with messy hair and a scruffy beard stood up and greeted me. He had an air of experience despite his appearance.
"Hello."
"You must be the client. Please take care of our Kyung-ah."
"Come on, senior..."
Despite his scruffy look, he was surprisingly polite.
"Go on and talk inside."
There were two others in the lab, but only he greeted me. One was passed out on a desk, and the other was muttering to himself while staring at a monitor, typing rapidly.
"Over here, please."
Kyung-ah led me to her desk in a corner. A cute succulent plant sat beside her monitor, and everything was neatly organized.
It was spotless, like she took great care of it daily. The atmosphere at her desk felt different from the others.
'I like this.'
I didn't need some genius who ignored their surroundings. I needed someone who could handle their work cleanly and precisely.
"Have a seat."
She pointed to the chair next to her own. I appreciated that she had already prepared a seat for me. Hopefully her work was just as tidy.
"Let me show you how to use it on your phone first."
When she launched the app on her phone, it brought up an interface similar to Daebak Securities. Of course, the graphics were on another level, but it had been built to resemble an actual trading app.
"This is a test app simulating a fake securities platform. I only implemented the menus needed for your requested features. The text is similar, and the stock prices are generated randomly. Now, when I run this..."
She launched another program. Just as I had requested, a screen appeared where I could input tomorrow's stock prices. There were five rows where I could enter the stock code, name, and target sell price.
The date was auto-filled for the next day.
"After entering the details, we run the program. I've set it to 48x speed."
Once executed, the program began rapidly buying stocks. Then, as the day shifted to the next, it started selling once the price targets were hit. If the stock dropped below the target price, it would pause; once it rose again, selling resumed.
"Right now it's connected to the test platform, but the final file will be linked to Daebak Securities as requested. Don't worry. I figured you'd want to see the numbers..."
"Looks good."
We stared blankly at the phone screen for about 30 minutes.
"What happens if there's a large sell order at the target price and the stock drops?"
"The sell is placed at that price. But if you want, I can change it so that the system waits for a drop of a certain percentage, and if it happens, it sells everything."
"Set it to 2% please."
"Okay."
She opened the code, found the value set to 0, and changed it to 2. Then she ran the program again.
"This time, it's running at 200x speed. I'll do five cycles and then show you the results."
"Sure."
After a while, the computation finished, and she brought up another window.
"On the left are the results from 400 test cases I ran. On the right are the ones we just did."
The left side had a massive dataset.
"And this is the result from a manual simulation without the program. The numbers match perfectly."
"Out of 400, not a single error?"
"None. Now let's calculate today's run."
She explained the complex formula in detail. It was a slightly improved version of the one I had initially written.
'As expected of KAIST.'
I nodded as she spoke, listening carefully. After deriving the numbers from the improved formula, we compared them to the program's actual run.
"They match."
"Yes. And the source code is stable. As long as there's no issue with the internet connection, it'll run without error. I kept it as light as possible."
She smiled shyly, but her eyes sparkled with pride. With the program verified, it was time to pay.
"Alright, then..."
As I stood up, Kyung-ah stopped me.
"Wait, I also added a bonus feature."
"A bonus?"
"It organizes the logs and emails them to you. I figured you'd want to analyze things later, since you even brought your own formula."
Perfect. I liked her thoroughness—even doing things she wasn't asked to.
"So, to use it..."
She explained with such passion and excitement that it made me smile. When she talked about the program, all traces of her usual shyness vanished.
"That's everything. Is there anything you didn't understand?"
"No. It's perfect."
"And just in case, I made a guidebook too..."
She handed me a spring-bound notebook, about 30 pages thick. Inside were concise explanations of each menu.
'She did all this in such a short time?'
Just like Professor Lim said, she was meticulously detailed. If the chance came, I really wanted to work with her someday.
"If you have any questions, feel free to contact me."
"Kyung-ah."
"Yes?"
"Now that we've settled the payment, how about lunch?"
"Lunch?"
"Yeah. I skipped breakfast. Do you know any good places nearby?"
Nothing builds rapport like sharing a meal.
***
After settling the contract with Professor Lim and paying the remainder, we headed to a Mexican restaurant near campus for lunch.
I recalled our conversation and couldn't help but smile.
> "There's a good Mexican place and a rice soup spot… maybe the rice soup would be better."
> "I think Mexican sounds good."
She had mentioned the Mexican place first, so I figured that's where she really wanted to go, but suggested the cheaper option out of consideration. Graduate students usually have tight budgets.
> "...It's a bit pricey."
Exactly what I expected.
> "It's on me."
> "Oh no, I couldn't! You already gave me the job..."
The way she panicked and waved her hands was endearing. People who don't take kindness for granted make you want to do even more for them.
Besides, I was rich—and about to get even richer—so buying a meal was nothing.
> "Consider it a favor for future updates. Let's go to the Mexican place."
> "If it's like that..."
It turned out to be quite a fancy restaurant, which made conversation easier. If we'd gone to a noisy rice soup place, we wouldn't have been able to talk freely.
When familiar faces are around, you tend to hold back.
> "If I want to ask for something later, can I contact you directly?"
> "Please go through the professor..."
> "But I'd like to contact you personally. It's kind of a private request, so it's awkward to involve him."
It took some persuading, but persistence paid off. She eventually agreed that depending on the request, I could reach out—or go through the professor.
Once someone gets involved, it's hard to walk away. Drizzle gets your clothes wet before you know it.
Eventually, she would become "my person."
***
'This is seriously convenient.'
All I had to do was input tomorrow's stock prices, and the program handled everything else. I kept a second phone connected and running the program, while the trade history was sent to my main phone.
It was a smart system, handling even split purchases with finesse. Sure, buying prices crept up a bit, but even if I did it manually, I couldn't do it better.
'This thing's a jackpot.'
The numbers kept rising and falling as the evaluation balance increased.
The program chose stocks with the highest expected returns based on my inputs.
> [Trade Executed: Bought 272 shares of Younghoon Industries]
> [Trade Executed: Bought 123 shares of Marine Transport]
> [Trade Executed: Bought 27 shares of Kangho Holdings]
> [Trade Executed: Bought 374 shares of WithPartners]
'Fast too.'
Before I could even blink, the program had already executed trades. When it came to routine tasks, it outperformed me.
'But the key is information.'
I was the only one who could use this program to make real money—because no one else knew tomorrow's prices.
Other people wouldn't need a system this complex just to manage sell prices.
The program sold off the stocks it had bought:
> [Trade Executed: Sold 123 shares of Marine Transport]
> [Trade Executed: Sold 27 shares of Kangho Holdings]
> [Trade Executed: Sold 374 shares of WithPartners]
The red numbers for evaluation gain flashed on and off, and my balance started rising exponentially.
**Program Day 1**
13.62 billion → 14.66 billion KRW (+8%)
**Profit: 1.045 billion**
'Even without 10% returns, I'm making billions now?'
**Program Day 2**
14.66 billion → 15.35 billion (+5%)
**Profit: 687 million**
'Well, 5% is the minimum. Some days are like this.'
**Program Day 3**
15.35 billion → 16.99 billion (+11%)
**Profit: 1.63 billion**
'Nice. Not bad at all.'
**Program Day 4**
16.99 billion → 20.66 billion (+22%)
**Profit: 3.67 billion**
'Damn. 3 billion in a day? That's insane.'
Just looking at it made me grin uncontrollably.
'This really is the magic of compound interest.'
Starting with just 10 million won, I had reached over 2 billion in less than two months. That was a 20,000% return. Even the 3,500% return in the first month was huge, but compounded, it became astronomical.
'I could probably afford a Gangnam apartment now.'
Back when I worked, it was just a dream. But now, it was within reach.
'I'm not withdrawing it yet—need to grow the seed money more.'
Still, even just thinking about it made me happy.
As I grinned like a fool, a pop-up suddenly appeared before me.
> [Your assets have reached 2 billion KRW. A new level is now unlocked. Would you like to proceed with the quest?]
> [Clench your right hand to accept, or your left hand to decline.]
'They're offering more now?'
Without hesitation, I clenched my right hand.