Yan found Gu in the library annex with the Ashen Marrow and Blood Ignition records spread across a worktable. The pages were open beneath small weights to keep the edges from curling. Bai sat on the windowsill with a fee ledger and waited for Yan to finish before he collected payment for the next courier run.
“Zhao asked about Blood Ignition,” Yan said.
Gu set his brush down. “What did he ask?”
“Who gave me the method. When we reconstructed the last breath. Whether I feel weak, whether the cost was delayed, how often I used it, and how much qi I had.”
“What did you answer?”
“I found the fragments among confiscated papers. You helped rebuild the sequence. I practiced it before the rescue, then used it once beneath the beam. I said I had not measured the reserve exactly.”
“Good. Don’t invent a number for a question you didn’t record.”
Gu pulled Yan’s notes closer. “Show me the entry you gave Zhao.”
Yan opened his notebook to the first low-charge use. It listed the sequence, the breath count, and the time he waited between cycles. The qi reserve was described as low but not measured. Gu read it without criticizing the missing number.
“Could I estimate it now?” Yan asked.
“Only if you label it as a later estimate. It would not turn the earlier test into a measured one.”
“I won’t.” Yan drew a line through an empty column where he had considered adding a figure. “I can compare the pulse before and after. I can’t recover a count I didn’t make.”
Bai tapped the fee ledger. “The courier records have the same problem. I know the sack left at the east gate, but if I didn’t weigh it, I don’t write a weight.”
Gu nodded. “That is the difference between a useful record and a confident story.”
Bai looked up from the ledger. “If Zhao wants a stable method, the library should sell him the manual at a premium.”
“The fragment is not complete,” Gu said. “It is not a product.”
“Is the complete copy?”
“No.”
“Then why are we discussing price?”
Yan laughed. “The payment would need to include the years the art returns to me.”
Gu gave him a flat look. “You are not selling that as a claim.”
Yan looked at the closed door of the case. “When you first read the warning, you thought the sequence would injure me.”
“I thought it would injure anyone who practiced it. That is what the text describes.”
“And after I used it?”
“Your bone held. Your channels remained clear. I recorded that. It does not rewrite the warning.” Gu’s voice stayed even, though his hand had paused over the page. “A result can be real and still belong to one person.”
Bai leaned his shoulder against the shelf. “Then I’ll keep my route. I don’t need to be the next person proving the rule.”
Yan smiled. “You can still carry the manual.”
“I charge by the weight.”
“I’m not. I’m answering Bai.”
Bai closed the ledger. “I heard you use the art in the courtyard. You felt stronger afterward. That much I can say.”
Gu nodded. “That is an observation. I watched him practice. I will not claim the art is safe for an ordinary cultivator.”
Yan moved the two fragments into a line. “You gave me the complete instructions and watched each activation. Would you have taught it if you had known its cost would reverse for me?”
Gu considered the question. “I taught the text because you asked to understand it. I knew the warning. I did not know what would happen to you. The result was yours to discover.”
Bai folded the fee ledger into his satchel. “I’m content not to discover a technique that takes years off my life.”
“That is a sensible choice,” Gu said.
“I was hoping for a more profitable answer.”
Yan pointed to the open text. “The last breath is easy to misunderstand. Zhao asked how much qi I had.”
“Show us where your reserve matters,” Gu said.
Yan traced the route from the chest through the limbs and back to the dantian. “The burst uses the qi already gathered. The life cost pays for the technique’s surge. For me, the life part becomes vigor, but the qi still runs down.”
Gu checked the line in the complete copy. “That is how the method is written. The final breath closes the circulation. Without it, the sequence would remain open and the ordinary cost could worsen.”
“Repeated practice still works,” Yan said. “It doesn’t stop after one use.”
“Yes. But each activation still draws qi. Your result does not change the text’s cost for anyone else.”
“I know.”
Bai leaned over the table. “Could the art keep a courier awake through a double shift?”
“No,” Yan said. “You would be paying years for a few hours.”
Bai looked toward the warning page. “My route can wait until morning.”
“You say that now,” Gu said. “Tomorrow you’ll complain the morning customers are slow.”
“I can complain after I sleep.”
He pulled the fee ledger back out and wrote down the next courier times. The joke had left him thoughtful. He had seen Yan’s strength, but the warning still described what the technique would do to him.
Gu asked Yan to explain the pause mark after each cycle. Yan followed the diagram, naming where a cultivator should settle the qi before starting again. Gu corrected one phrase, not because Yan had drawn it wrong, but because the old notation could mean either a breath or a full pause.
“Which one did you use?” Gu asked.
“A full breath. I waited until my pulse settled before the next cycle.”
“Then write that as your personal observation. Keep it apart from the manual’s instruction.”
Yan labeled the margin: “My test: pause until pulse steadies.” He did not insert it into the original copy. Gu read it and approved the separation.
Bai watched him write. “You have a note for every meal, pill, and breath.”
“Only the ones I want to remember.”
“Then you should record that this conversation was worth one free bun.”
“It was worth half a bun.”
“Half is a start.”
Gu gathered the fragments and returned them to the dry case. “The text is complete. The danger remains for ordinary users. Yan’s result is not a recommendation.”
Bai picked up his bag. “I’ll keep my routes and my ordinary lifespan.”
Yan closed the case. He liked knowing how the sequence worked. He liked that he could use it without the feared collapse. Neither fact made the old warning false for anyone else. The manuals would stay locked between trials, and Zhao had only his pulse readings and the answers Yan chose to give him.