The "earth" Li Ce referred to was not common soil or mineral-rich rock, but rather a special kind of clay used in the heat treatment of blades. The process, known as clay tempering, is deceptively simple: a carefully formulated layer of clay is applied to parts of the blade that do not require high hardness. The blade is then heated in a furnace to a precise temperature, removed with tongs, and quenched in cold water. The exposed edge, lacking the protective clay, hardens rapidly, while the clay-covered sections cool more slowly, retaining flexibility. The quicker the quench, the harder the steel; the slower the cooling, the tougher the blade. And only a tough blade can resist breaking under stress. Craftsmen had long since mastered the art of controlling this differential cooling process with remarkable precision—hence, Li Ce suspected the issue lay not in the technique, but in the clay itself.
"What's wrong with the clay?" Ye Jiao narrowed her clear, alluring eyes, swirling the dusty residue in her palm.
"It must be adhesive enough to insulate against water," Li Ce said with quiet intensity. "Otherwise, once the blade hits the water, both edge and spine cool simultaneously and harden the same. A uniformly hardened blade is brittle and prone to snapping."
"In other words," Ye Jiao's gaze turned to the distant forge, her expression solemn, "the shaping, blending, smelting, and forging—none of those were at fault. Even the minerals and other materials were flawless. Yet this humble, oft-overlooked clay... it's not what it used to be."
A spring breeze lifted a swirl of dust through the estate of the Duke of An, dispersing it among the blossoming peach branches.
"Exactly," Li Ce agreed. "There are too many impurities in this batch, and a faint odor too—though I can't quite place it. But if it's truly the clay, we'll know with a single test."
The mingling scents of blossoms and smoke in the air made any olfactory distinction difficult. Testing was straightforward, but acquiring a new batch of suitable clay would be anything but. The military arsenal's supply was off-limits, and in the capital, few smithies possessed the expertise for clay tempering.
"How about this," Li Ce suggested, "we inquire at the Wu Hou smithy. See if there are any newly arrived clays in the city that haven't yet been claimed by the arsenal. We can borrow a sample."
At the mention of Wu Hou, Ye Jiao's expression shifted.
"No need," she said curtly. "Let's not involve the Wu Hou smithy, nor trouble Liu Yan."
She didn't trust Bai Xianyu, hence her reluctance to deal with Wu Hou. As for Liu Yan, she simply didn't want to entangle him in this matter.
Understanding her unspoken thoughts, Li Ce smiled knowingly and nodded. "I'll send Qingfeng beyond the city walls. He'll bring a small sample back—Wu Hou won't even notice."
The plan was thus decided. Ye Jiao said nothing of the clay swap to the craftsmen.
The next day, Qingfeng returned with the new clay. Ye Jiao asked, "Did the gatekeepers notice anything?"
"I sealed it inside a bamboo tube. No one saw," he replied.
She nodded, reblended the clay herself, and when the craftsmen were distracted, poured it into the ceramic jar.
That day, a new 陌刀 was forged. After a rough edge grind, Ye Jiao and Qingfeng each gripped a horizontal blade, stood several paces apart, and prepared to test them.
Spring sunlight bathed the yard, a gentle breeze curling around the pristine blades. Ye Jiao raised her sword; her expression turned steely in an instant.
Across from her, Qingfeng dared not let his guard down. He charged, their blades meeting after a few swift exchanges. Suddenly, Qingfeng lunged, and Ye Jiao leapt from the peach tree, flipping mid-air before bringing her blade down with a thunderous strike.
Steel met steel with a deafening clang. A jolt numbed Ye Jiao's hand, while Qingfeng, though he managed to hold on, was forced back several steps by the sheer force.
Once steady, both instinctively looked down at the weapons.
Though Ye Jiao's blade bore a small notch at the edge, the body of the sword remained unscathed—no cracks, no fractures.
"It worked!" cried Shuiwen, the young maid, cheering from a distance. Qingfeng glanced her way and grinned sheepishly.
Ye Jiao lifted her sword, brows curved with joy, and ran toward Li Ce, who had been observing the trial. She threw her arms around him.
"Sisi is amazing!"
"No, you're the brilliant one," he replied indulgently, smiling as she shook him gleefully. His fingers slid down her wrist and gently removed the blade from her grasp. "Does your wrist hurt?"
"Qingfeng's probably hurts more," Ye Jiao said, chuckling. "I used finesse. He took it head-on."
Rubbing his sore palm, Qingfeng remarked, "I heard you used to lose to Zong Quanwu. I think you'd win now."
He dared speak, but not look at the two of them—his gaze flitting away from their affectionate closeness.
Ye Jiao was thrilled. Coming from Qingfeng, the most skilled of Li Ce's retainers, it meant her hard work these past months had truly paid off.
"Tomorrow marks the seventh day," Ye Jiao declared. "I'll march into the arsenal and slap this blade right on Director Wang's table. He'll have no choice but to change the clay."
"Tomorrow is also the Crown Prince's investiture ceremony," Li Ce said solemnly. "I must remain at the Daming Palace."
"Then go," she replied, releasing him with a grin as she gazed at her blade, unable to contain her excitement. Her brother had been wrong—appointing her as the Ministry's Armaments Physician was the emperor's wisest move yet!
The message sent by Prince Zhao, Li Jing, lay on Li Zhang's desk. He glanced at it once, then pushed it aside to continue his paperwork. The investiture ceremony was tomorrow, but the Ministry of Rites would handle the proceedings. He dared not relax—he had to review every memorial before more piled up the following day.
Sometimes he frowned; at other times, his expression turned scornful. Mostly, though, he read with calm precision, jotting notes and judgments, stacking the approved reports neatly aside.
Finally, the last document was done.
A court official stepped forward to collect the stack. Only the letter and a slightly soiled book remained on the desk.
Li Zhang glanced at the letter. "What's the situation with the arsenal's 陌刀?"
"The arsenal's been uncooperative," the official muttered. "Physician Ye dragged the craftsmen to her own estate. The Duke of An's manor hasn't had a quiet day since."
His words dripped with disdain—hardly surprising given his animosity toward Ye Jiao.
Li Zhang smiled faintly and tossed his brush into the wash. "Still haven't identified the problem?"
The official shook his head.
"It's not the technique," Li Zhang scoffed. "Then it must be the materials. Ore composition, impurities, even the clay. Li Ce's far too clever to come begging to me."
The official nodded and withdrew respectfully.
At that moment, a waiting attendant entered. "Your Highness, I've discovered something. It pertains to the arsenal."
"Speak." Li Zhang opened the book, eyes skimming the page indifferently.
"The director, Wang, petitioned Prince Wei for help. Prince Wei agreed."
"What was the request?"
"His relative in the Ministry of Revenue was caught selling seed stock illegally."
"When did this happen?" Li Zhang's gaze sharpened.
"Last month," the attendant replied. "Also, the arsenal's been constantly moving equipment, claiming they're reorganizing due to warmer weather. But insiders say even they often confuse the storage rooms now."
A faint smirk crossed Li Zhang's lips.
"Let them exhaust themselves with their petty games," he said coldly. "After tomorrow, none of it will matter."
As night deepened, the Emperor of Great Tang also found no rest.
"Gao Fu."
The lights were mostly extinguished, yet he still called out.
"Your servant is here," Gao Fu stepped forward, lifting the curtain with care. "Your Majesty, what is your command?"
"How is that girl?" the Emperor asked. "No word from her in days."
He didn't need to specify—Gao Fu already knew.
"She's forging blades at home," he chuckled. "Your Majesty truly picked the perfect Armaments Physician for our Great Tang."
"Should've had her composing songs in Pear Blossom Court. At least she'd have more leisure." The Emperor grumbled, but the image of her hammering away at steel made him chuckle again.
"Tomorrow is the Investiture Ceremony," he sighed softly.
"Indeed," said Gao Fu. "Long may the Tang Dynasty endure—it is a day to rejoice."
The Emperor nodded solemnly. After a long pause, he asked, "And Li Chen? Has he behaved himself?"
Gao Fu hesitated slightly before replying...