The replaceable practice slab had a metal rim around its face. Gu had marked the strike line farther inward after Yan’s last test, and the wood beneath it showed where the old face had split cleanly.
Yan checked the braces before stepping into place. The Ashen Marrow sequence felt familiar now. The marrow warmth from his earlier circulations remained a quiet strength beneath his bones. The rim still sat close to the marked line, though from his stance it seemed farther away.
“First strike only,” Gu said. “Then we inspect the face.”
Yan nodded. He gathered a small charge, followed the three measured breaths, and sent the force through his arm. The slab cracked cleanly along the chalk line. The blow pressed his knuckles to the metal edge. He heard the contact and felt the sharp bite of it a moment later.
He pulled his hand back. Skin had split across two knuckles. A bright line of blood welled along the cut.
“Stop,” Gu said.
Yan swore under his breath and shook out his hand. The strike’s internal strain had changed into firm warmth through his marrow. The metal rim had not. His knuckles stung, and the blood ran down toward his wrist.
Gu brought clean cloth and a basin of water from the alcove shelf. “Sit.”
“I can clean it.”
“You can clean it sitting down.”
Yan lowered himself onto the bench. Gu set the basin beside him. Yan dipped a cloth into the water and pressed it against the cut. The first touch made him wince. The blood diluted into a pink streak in the basin. His bones felt sound beneath his skin; the pain came from the split flesh.
“Does the marrow hurt?” Gu asked.
“No. The cut does.”
“Do you want to stop for the day?”
“I’ll stop striking until the skin closes. I can still study the angle.”
Gu gave him a strip of clean cloth. Yan wrapped it around his hand and tied it with his other fingers. The knot was loose, but it kept the cut covered. The rim had nicked him from outside. The System had changed the method’s internal cost, not the force that struck the target or the metal that caught his hand.
Gu turned the slab so the light fell across the rim. “You hit the face, then your knuckles carried through to the metal.”
“It looked farther from the line.”
“From your stance, the rim was hidden behind the edge.” Gu placed his hand where Yan’s had landed. “The face is replaceable, but the frame is not soft. We need to move the mark inward.”
Yan flexed his fingers. The cut stung under the cloth. “I thought the force would stop when the slab split.”
“It stopped when your arm stopped. Your hand still had to travel through the rest of the motion.”
They examined the slab from both sides. The rim sat a finger-width closer to the strike line than it appeared from Yan’s angle. Gu chalked the new mark inward, then asked Yan to repeat the movement without qi.
Yan stood, careful not to open the wound. He moved his feet, turned his hip, and brought his fist along the route. At the release point, he stopped with his knuckles short of the rim. He adjusted his wrist and tried again. This time the fist passed along the face without touching the metal.
“The strike turned my wrist outward,” Yan said. “I was still following the force when my hand reached the rim.”
“Good. Don’t finish a motion after you’ve already lost the line.”
“I’m glad it was a shallow cut.”
“So am I.” Gu checked the cloth. “The marrow reinforcement did not make your skin invulnerable. This is an external injury from a bad angle and a hard rim.”
Yan looked at the cracked face. “The manual should have warned me about cheap target construction.”
Gu laughed despite himself. “Most manuals assume a competent carpenter.”
They both looked at the badly made frame. One screw sat crooked in the wood, and the metal lip had not been filed smooth. Gu promised to replace the rim before the next practice. He asked Yan to keep the hand dry and stop striking until the cut had closed. Yan agreed, then returned to the bench while Gu found a tighter bandage.
Gu brought a short wrench from the tool shelf and tried to loosen the crooked screw. It turned once, then caught. The metal rim had bent over the wood, leaving a sharp hook at the corner. Gu wrapped the wrench in cloth and pulled the screw free without putting his bare fingers near the hook.
“Can you flatten it?” Yan asked.
“Not without taking the whole frame apart.” Gu set the rim on a shelf away from the other tools. “I’ll ask the carpenter for a filed replacement. This face is out of service until then.”
Yan wanted to help, but the bandage made his fingers awkward. He held the notebook open while Gu marked the repair needed and crossed the slab off the practice list. The target would not be used again until the sharp edge was gone.
The cut stung each time he flexed his fingers. Gu unwound Yan’s loose wrap, cleaned the edge once more, then folded the cloth into a neater pad and tied it securely. He did not tell Yan the injury would vanish. He said the skin needed time to close and that they could inspect it at the next lesson.
Yan opened the reject map to a clean page. This was not a pill, but he wanted a record of the two different harms. He wrote: Ashen Marrow strengthened the marrow and bones; the external strike against the metal rim split the skin. Gu checked the words and added the time and location of the injury.
“Don’t write that the technique caused no harm,” Gu said.
“I wrote that it strengthened me.”
“Good. The cut came from the rim, but it happened during the practice. Someone reading this should know both.”
Yan nodded. He recorded that the strike line sat too close to the metal edge from his stance. He had been glad the error produced a shallow cut instead of a broken bone, but the marrow reversal had not created that safety. The slab’s construction and his own angle had mattered.
Gu studied the next mark. “The rim will be replaced before you practice again.”
“Can you find one that doesn’t bite?”
“I can find one that was filed.”
“That sounds like an improvement.”
“It is the best I can promise.”
Yan held his hand against his chest so the bandage would not catch on the table. The marrow warmth remained. The cut hurt each time he moved his knuckles, a plain and local pain that the System had not changed. He had learned where the force went inside him and what the metal did outside it.
Gu packed away the chalk and checked the target frame again. “No more strikes until the hand is ready.”
“I’ll study the angle.”
“Only the angle.”
Yan gave him a tired smile. “Only the angle.”