Walnut Tree
Dan Seol-yeong enjoyed life in Luoyang.
She liked the bustle of people, she liked the endless spectacles that appeared every day.
Even assisting a carpenter—holding a plane and chisel, carving and shaping wood—suited her temperament.
But what she liked most of all was the evening, when she came back from work and shared supper with Tang Mujin.
Not long ago, supper for her had only meant filling her stomach before lying down alone, waiting for sleep to come.
It had been a time to brood on her loneliness, to dwell on the endless path she had to walk. From her childhood up until the summer just past, it had always been that way.
Yet in just a few months, her most hated time had become her most cherished. Such is life's unpredictability.
What should I suggest we eat today?
That thought was on her mind when she returned to the inn and saw Tang Mujin, anxiously packing and unpacking his belongings in agitation.
Her eyes narrowed.
"…What are you doing?"
"I have a bad feeling."
Mujin explained the situation. The Medical Sage had been murdered, and he worried that the old man too might have been caught up in misfortune.
Seol-yeong hadn't spent a long time traveling with Goiyi, but when she recalled how he had behaved, she felt Mujin's worries were excessive.
Hadn't he subdued Baek Choo-seo, a first-class master, as if handling a child, and slaughtered black-clad assassins as though merely stretching his limbs?
"That old man isn't the sort to suffer misfortune—he's more like the sort to cause it."
"You're right. But something he said before we parted keeps bothering me."
Seol-yeong set aside her preconceptions and reconsidered. The old man had spoken more than usual that day, and the black-clad assassins had seemed intent on targeting him specifically.
Yes. This wasn't just idle worry.
"What do you think happened, then?"
"He said he had personal business. I think it had something to do with the Medical Sage."
Mujin drew in the dirt. The drawing was clumsy, not like him.
In the southwest he marked Sichuan, in the southeast Anhui, and above them wrote Luoyang. Then he drew a line between Anhui and Luoyang.
"Now that I think about it, from the time we took the boat down the Yangtze until we reached here, we've always moved northwest. At the time, I thought it was just because we were headed to Luoyang."
He extended the line beyond Luoyang. At the end, he wrote a new name: Bongshan.
"The Medical Sage lived in Bongshan. If you keep going past Luoyang in the direction we've been traveling, you reach Bongshan. Maybe the old man's destination was Bongshan all along."
It sounded plausible. Seol-yeong nodded.
"And then?"
"Maybe he went to meet the Medical Sage, and that's when black-clad assassins or his enemies appeared, trying to harm him. In the chaos, the Sage was killed."
"Have you heard whether the old man was injured?"
"No. But we haven't heard that he's safe either. That's what bothers me."
Seol-yeong stared at him.
It was speculation riddled with holes. In her view, the Sage's death likely had nothing to do with Goiyi at all.
Besides, Goiyi was no helpless man. He was cunning and strong.
Yet she also knew that such unease would never fade until directly confirmed.
So she smacked Mujin hard on the back—smack!—and the anxious look faded from his eyes, his usual sharpness returning.
Mujin grumbled.
"Why hit me?"
"What are you agonizing over? Go to the clinic right now, tell them you'll be taking time off, and let's go. Better to see with your own eyes than keep fretting."
"And you?"
"Of course I'm coming. You think you can just leave me behind?"
Even if Mujin's guess was wrong, it didn't matter. The trip would be cold and difficult, but they could treat it as just another journey together.
Seol-yeong smiled with her usual confidence.
****
Though they would have preferred to join a northbound caravan passing Bongshan, doing so would mean waiting at least five more days in Luoyang. So the two of them set out immediately on foot.
A few days later, with a guide they hired for three copper coins, they reached a small clearing halfway up a low mountain. Nothing stood there.
"This is where the Medical Sage lived."
"…But there's nothing. I heard half-burned ruins remained."
"The villagers tore down the house. After such a bloody incident, it's best to remove it quickly. Besides, it wasn't in a state to be repaired."
Mujin scratched his head.
"Was there any sign of fighting nearby?"
"No one saw such a thing. This isn't deep mountain, but it's far from the village. Even if something happened here, it would be hard to know."
Mujin examined the site. There were no signs. He had half expected as much, but still felt relieved—Goiyi didn't seem to have been caught up in the fight.
Perhaps his earlier assumption—that Goiyi had gone to see the Sage—was wrong. Direction and timing might simply have overlapped by coincidence.
"If you'd like to pay respects at the Sage's grave, follow this path straight ahead."
"Thank you."
The guide departed, and Mujin and Seol-yeong went the way he had pointed.
There were two graves: one well-kept, the other freshly raised, the earth still bare. The place was quiet, peaceful.
Seol-yeong spoke.
"Shall we go back now?"
"…No. Let's go a little farther."
"How far?"
"Since we've come this far, I'd like to see Huizhou as well."
Before parting, Goiyi had said he would bury two medical texts beneath the walnut tree in Huizhou.
Just as they had followed their path from the Yangtze to Luoyang and then to Bongshan, a few more days' walk would bring them to Huizhou.
Mujin added:
"It would be strange to turn back now. Who knows, we might even run into the old man loafing about in Huizhou."
"And what will you say if you do?"
"I'll just tell him I came out of boredom. If I say I came because I was worried, it would be awkward."
"Fine. Let's go. Since we've come this far, there's no reason to stop short of Huizhou."
Her answer was cheerful.
Mujin looked at her then, finally finding ease in his heart.
This journey had been spurred only by vague suspicions and intuition, yet Seol-yeong followed without a single complaint, even in the bitter cold.
He suddenly felt guilty, but she instantly read his expression.
She smiled.
"What? Feeling guilty only now?"
"A little."
Seol-yeong glanced around. On the snowy mountain path, they were the only two.
She stretched out her left hand to him.
"Then at least warm my hand. It's freezing."
Mujin clasped her hand in both of his. Soft, yet calloused.
The two walked slowly down the empty snowy road, chatting idly.
***
On the way, they encountered a northbound caravan bound for Huizhou. Paying the fare, they climbed onto a cart drawn by a pack horse. The ride was rough and far from comfortable, but such things didn't matter.
Huizhou
Huizhou wasn't a large city, but merchants traveling to and from the Western Regions always stopped there to rest.
Of course, Mujin hadn't known that beforehand—it was something he heard from the traders they accompanied on the way.
"What business brings you young folks to Huizhou?"
"Someone I know mentioned there's an unusual walnut tree there. Thought we'd take a look while we're nearby."
"A walnut tree? There is a big one, but it's not exactly much of a spectacle."
"Still, since we've come all this way, we might as well see it once."
The merchant looked at Dan Seol-yeong and Tang Mujin for a moment, then nodded.
"Well, you don't look like the sort who need great spectacles anyway."
The merchants called them a young married couple. Mujin and Seol-yeong repeatedly explained that they weren't married, but the mischievous traders stubbornly kept addressing them that way.
They even joked, "Well, you may not be husband and wife now, but you might be someday."
Whenever that happened, Mujin would steal a glance at Seol-yeong's face. Her expression was subtle, hard to read—but she never looked displeased.
Riding the jostling cart, Mujin pondered. Why, of all places, had the old man chosen beneath the walnut tree of Huizhou as a meeting place? The answer was simple: surely Huizhou was Goiyi's hometown.
After parting ways with the caravan, Mujin wandered the streets of Huizhou, asking around whether anyone knew Goiyi. After questioning half a dozen people, an old man finally reacted to the name.
"Yi-chung? A fellow by that name left our town long ago."
"That must be him. Have you seen him recently?"
The old man shook his head.
"No. Never heard of him coming back."
"Do you know which house he lived in?"
"House? There's none left. The day he left, he burned it down. Nearly set my house on fire too, the bastard…"
And like all old men lost in reminiscence, his tale threatened to ramble on without end. Mujin quickly thanked him and took his leave.
There was no need to ask about Huizhou's great walnut tree. Just outside the village, on a small hill, stood a lone massive tree.
The two of them climbed the hill. In front of the walnut tree were two rounded graves—one large, the other smaller.
His wife and daughter, perhaps, Mujin thought.
He gently brushed the snow from the graves.
It was winter, so withered yellow grass lay flat atop them. But the grass wasn't overgrown, nor were there signs of wild beasts having dug into the mounds. Someone had surely tended the graves recently.
Mujin cleared away the snow between the graves and the walnut tree. There were faint signs that the ground had been dug up before. With his scabbard and bare hands, he clawed into the frozen earth.
After a while, a yellowed book emerged. Seol-yeong knelt to pick it up.
"So the old man really did come here."
But contrary to Goiyi's words—that there would be two books—there was only one.
Mujin brushed dirt off the cover and read the title. Manbyeongseo (The Ten Thousand Illnesses). A book of all diseases.
Opening it, he saw it was, like other medical texts, a record of symptoms and their treatments. But this wasn't meant to teach medicine to novices.
The content was dense—only those already versed in the Golden Casket Summaries, the Treatise on Cold Damage, and the Inner Canon of the Yellow Emperor could make sense of it. Even for Mujin, it was no easy read.
He slowly turned the pages.
The handwriting changed from time to time, as if multiple contributors had expanded the text. Each time, the scribe left their name: Yang Jun, Yang So-jong, Yang Tae-gok…
I'll have to study this carefully later.
As he flipped through, about to tuck the book away, his fingertips felt something odd. The last pages didn't turn smoothly; they were stiff, hardened. Not merely from the cold, but with another texture.
On the final leaf was a dark blotch, about the size of half a palm. That part of the paper was brittle, as though it had once been wet and dried stiff.
Mujin lifted the page to his nose.
Earthy damp, the smell of old paper—and faintly, beneath it, a trace of iron. Blood.
The scent was faint, but undeniable.
"What is it? Something strange?" asked Seol-yeong.
"Hm? No. Just… I like the smell of old paper."
Mujin deflected casually, but his thoughts raced.
It can't be what I think it is…
Instead of closing the book, he flipped back toward the place where the handwriting last changed.
There, beneath the new notes, was the name of the contributor.
Yang Heun. The same name as the Medical Sage.
The murdered Sage. A book bearing his name. A book stained with blood.
Mujin understood now what had happened—
and who it was the old man had gone to find.