Night had fallen.
The map was still spread out on the desk, the loop of the Hetao Plain circled in vermilion ink, glowing faintly under the lamplight.
Xu Qinghuan took a sheet of fine Chengxin Hall paper from the drawer, picked a weasel-hair brush from the rack, and dipped it generously into the inkstone.
As the brush tip touched the paper, she wrote four characters first.
“Dear Father, to be opened.”
After finishing these four words, the brush paused.
There was too much to say, and where to begin required careful thought.
She considered for a moment, then started with the situation at the border, using the briefest strokes: the Helian cavalry’s tactics of cutting off water sources, destroying grass, and besieging without attacking, slowly wearing down the Zhenbei Army through attrition. She covered these matters in minimal detail.
Her father in the capital had likely already learned of these from the Ministry of War’s dispatches, so there was no need to elaborate.
Then she shifted the brush, cutting to the core.
“…The thirty thousand troops in Zhenbei City rely entirely on grain shipments from the capital, which take over two months on the road, with half the supplies lost to spoilage. In the long run, this is unsustainable.”
“I have recently studied the northern border maps and geographical records and discovered a vast plain south of the Yin Mountains, inside the bend of the Yellow River. The soil is fertile, and the river water can be diverted for irrigation. It is truly a heaven-sent farmland.”
“However, for more than a hundred years, because of repeated raids by the Helian cavalry, the common people have dared not cultivate it, leaving it to lie fallow. In my view, if we could implement military farming here, having the Zhenbei Army grow their own grain locally, we could break our dependence on the capital’s supply chain once and for all, and establish a foundation of our own.”
At this point, Xu Qinghuan set down the brush and rubbed her wrist.
Saying these words was one thing; making them happen was as difficult as scaling the heavens.
She, Xu Qinghuan, understood accounting, knew statecraft, and could even direct Jenny Huang in making firearms. But she knew absolutely nothing about farming.
What soil to plant which grain in, how much water to apply in each season, how to improve saline-alkali land, how to dig irrigation channels—
These things could not be found in books, and the short videos she had scrolled through in her past life were too fragmented to form a coherent system.
She picked up the brush again, and the ink spread across the paper.
“…Father, with your convenience at the Ministry of Revenue, please search in the capital or the provinces south of the Yangtze for experts in water conservancy and agriculture.”
“Such talents need not hold official rank. Only those who have truly farmed, repaired canals, and understand the seasons and the properties of the soil are needed.”
“Also, the northern border is dry and bitterly cold, and ordinary grain seeds are hard to survive. I beg you, Father, to also seek out drought-resistant and cold-tolerant superior seeds, especially winter wheat, millet, and flax.”
“People and seeds—neither can be lacking! If you can send them north with the seeds within two months, we can still make the spring sowing next year.”
By now, the letter had filled nearly half a page. Xu Qinghuan was about to continue when hurried footsteps sounded outside the courtyard gate.
Thump, thump, thump!
The door was pushed open with a slap, and Jenny Huang strode into the study, her whole body still carrying the pungent smell of smoke and fire.
Her apron was covered in black ash and vegetable stains. Her hair was hastily twisted into a bun with a wooden hairpin, mostly already loose.
But what she held in her hands drew Xu Qinghuan’s gaze immediately.
It was a few thin leaves of dried vegetables, shriveled and wrinkled, yet their color was not the expected withered yellow but retained a faint layer of dark green.
Jenny Huang placed the dried leaves gently on the corner of the desk, careful not to soil the half-written letter.
“Miss!” she said, her voice barely containing her excitement. “The method you mentioned the day before yesterday—I thought about it all night, ruined three batches of vegetables in the furnace, and finally figured it out!”
Xu Qinghuan picked up a piece of dried vegetable, rubbing it between her fingers.
It felt crisp to the touch, without any musty dampness. She brought it near her nose and smelled a faint, clean vegetable fragrance.
“Tell me, how did you do it?”
Jenny Huang pulled up a stool and sat across from the desk, ticking off points on her fingers as she explained step by step.
“First, washing!”
“No need to say much about that—pick out the rotten leaves and any with insect holes. Keep the good leaves and cut them into thumbnail-sized slices. They have to be thin; if too thick, they won’t dry through, and moisture trapped inside will cause mold.”
Xu Qinghuan nodded. That step was easy to understand.
“Second, blanching!” Jenny Huang raised two fingers. “This step is the most critical—the one that made me ruin three furnaces before I got the timing right.”
“Load the cut slices into a bamboo basket and plunge the whole thing into boiling water. Not too long, and not too short.”
“I tried it out: count silently to a hundred. Once you see the vegetable color change from gray-green to bright green, fish it out immediately and dunk it into a prepared basin of cold water to cool it down.”
“Too long, and the vegetables turn mushy, with all the nutrients leached into the water. Too short, they don’t blanch thoroughly, the raw, astringent taste isn’t forced out, and no matter how you dry them later, they’ll be bitter.”
Xu Qinghuan’s brush had unconsciously stopped in midair.
She realized that this seemed to be the “blanching” process used in modern food processing. As for the specific reason why, she didn’t fully know herself.
Yet Jenny Huang, through trial and error, had worked out the entire technique.
“Third, smoking!” Jenny Huang lowered her voice, a note of pride creeping in. “This one I got from thinking about how sulfur soap is made.”
“After draining the blanched slices, spread them out on bamboo trays and bring them into a sealed little room. Light a small pinch of sulfur in the corner, let the yellowish smoke gently fumigate the slices for about the time it takes an incense stick to burn, then take them out.”
“After the smoking treatment, the green color of the vegetables holds up by seventy to eighty percent. I figure they’ll stay without turning black for ten to fifteen days. I even tested it—after soaking the smoked vegetables in water, the color and taste are almost the same as fresh.”
Xu Qinghuan put down the brush.
Sulfur fumigation for color preservation and anti-rot.
For Jenny Huang to extrapolate this from her knowledge of sulfur soap—this ability to draw analogies was truly a natural gift.
“Fourth, drying.” Jenny Huang stood up, walked to the wall, and traced a square shape on the white plaster with her finger.
“I designed a drying room. At the base, I lay a row of fireboxes. But the vegetables are not placed directly above the fire—there’s a curved flue in between. The fire heats the air, and the hot air rises along the flue, coming out through tiny holes at the bottom of the drying room to blow evenly over the vegetable slices on the racks.”
“The advantage of this method is that the vegetables never touch an open flame, so they won’t get burnt. And the hot air is circulating, carrying the moisture away.”
“I tried a batch last night. I kept the fire going from evening until morning, and the slices dried through completely. When you pinch one, it snaps with a crisp sound.”
Jenny Huang turned around, her eyes gleaming.
“Oh, and there’s another thing. Those abandoned cave dwellings outside Zhenbei City—they’re cool in summer and warm in winter, a natural spot for air-drying! If the volume is too large for the baking room, we could hang the slices in the caves for sun-drying. It’s slower, but it saves firewood, and the cost can be kept even lower.”
Xu Qinghuan, after hearing the four steps, had already linked the entire process into a complete chain in her mind: washing and slicing, boiling water blanching, sulfur fumigation for color retention, hot air drying.
Every step had clear operational standards and assessment criteria.
But she did not rush to praise. Instead, she pressed further.
“What about after drying? How do you store them? If you put them in cloth bags, with the wind and sand of the northern border, they might reabsorb moisture, and all your work would be wasted.”
Jenny Huang slapped her apron, raising a small puff of black ash.
"I've figured that out too! Use earthenware jars, layer the dried vegetable slices one by one, pressing them down firmly. Place a pack of quicklime at the bottom first—the same white lime blocks we use for building houses; that stuff absorbs moisture better than anything else."
"Once the jar is full of vegetable slices, cover the top with oiled paper coated in tung oil, and finally seal the mouth of the jar with yellow mud. I tested one jar, left it for five days, and when I opened it, the inside was as dry and crisp as if it had just come out of the oven. The lime pack barely gained any weight."
Xu Qinghuan picked up a slice of dried vegetable and dropped it into the teacup on the table.
As the cold tea soaked in, the shriveled leaf slowly unfurled, its color shifting from a dull green back to a pale emerald. Though the revived leaf wasn’t as plump as fresh ones, the hint of green was unmistakably there.
That was enough.
Xu Qinghuan fished the rehydrated leaf out of the teacup, held it in her palm for a moment, then turned and sat back down at her desk.
She picked up her brush and continued writing below her letter to her father:
“…There is another matter, one that concerns the lives of the entire army.”
“Jenny has successfully developed a method for dehydrating vegetables. It removes the moisture from fresh greens while preserving their essential qualities, turning them into dried vegetables that can be sealed in earthenware jars. They will remain unspoiled for months, ready to eat after soaking in water, with their vitality and medicinal properties still intact. This can completely cure the strange illness suffered by the border troops from prolonged consumption of stale provisions.”
She wrote out the four procedures in detail—blanching, sulfur-fumigation, hot-air drying, and lime sealing—using concise language but step-by-step clarity, ensuring her father could understand every stage upon receiving the letter.
After finishing the process description, Xu Qinghuan’s brush did not stop.
“…Should this method succeed, it will benefit more than just the border troops.”
“Every provincial garrison, every canal boat crew, every mine laborer—anyone far from where vegetables are grown—will have a need for this! We must select a secure location in the capital to secretly establish a dehydration workshop. First, supply the northern frontier under the pretext of military provisions, then plan for broader distribution.”
“This product is cheap to produce, but its price can be set comparable to medicinal herbs, because in essence, it is a lifesaving remedy.”
“If our Xu family can monopolize this technique, half of the empire’s military supplies will pass through our hands. This isn’t about silver—it’s about giving the Xu family an unassailable pillar of power in the court.”
With the last line written, Xu Qinghuan set down her brush.
She picked up the letter, read it silently from beginning to end, and confirmed there were no errors. Then she folded the paper, slipped it into an envelope, took out sealing wax and her personal seal, melted the red wax over the flame, and let it drip onto the seal flap. She pressed the copper seal down, leaving a crisp impression of the character "Xu."
“Li Sheng,” Xu Qinghuan called out.
Li Sheng strode in quickly from outside.
Xu Qinghuan handed the envelope to him, her voice grave: “Choose the most reliable man you have. Travel by land, day and night, and deliver this to the Xu residence in the capital.”
“This letter concerns the survival of the northern border. There must be no mishap. If you encounter an inspection on the road, better to destroy the letter than let it fall into anyone else’s hands.”
