91: Chapter 91: War Countdown - Every Position is Nailed to the Simulation Table

Three hours before dawn, the notice for the war council was delivered to everyone.

It was not via communicator—Yang Shitou's relay station was maintaining full-spectrum silence, transmitting no excess signals other than a fixed beam directed at Terra.

He used paper. Seventeen scraps torn from production logs, handwritten in charcoal, with the same time and location printed at the top of each: the first quarter-hour after daybreak, the second-floor assembly room of the Arsenal.

There were two reasons for choosing the assembly room instead of the Intelligence Center.

First, the wall cavities were embedded with three layers of soundproofing panels that Old Tom had fashioned from scrap spring steel—the sound of the forging hammers outside was reduced by three-quarters, yet not a whisper of the conversation inside could leak out.

Second, the assembly room windows faced east. The morning light at the first quarter-hour after daybreak would cut in at an angle, falling onto the map of Hope Star on the table, causing the markers for the swamps and the Salt Flats to cast a shadow offset by one millimeter.

This slight offset was negligible on an ordinary map. But when Lin Mo had set the table alone in the early hours, he had placed three iron filings, each the size of a grain of salt, at the start and end points of the projection offset—each one corresponding to a possible coordinate for a Chaos signal relay station.

When Alice entered, her first glance did not fall on the map, but on those three iron filings.

Yang Shitou arrived first. He copied the last set of calibration records from the previous night and placed them on the corner of the table—without waiting for Lin Mo to ask, as it was his implicit understanding that before the war council began, the signal status should be laid out on the table.

The remarks column in the last line of the record read: "Unknown echo interval reduced to forty-seven minutes. Intensity + 3dB." There were no exclamation marks, as the communications corps' regulations never used exclamation marks—yet he had drawn a horizontal line under this line of text. Yang Shitou never drew horizontal lines.

Locke arrived second. He came directly from the entrance of the Medical Station, the dew of the early morning still clinging to his axe blade.

He propped his laser axe against the inside of the doorframe, wedging it perfectly into the notch Old Tom had chipped out while moving spring steel last time, the handle steady and slip-proof.

Locke knew of this notch. Every time he came, he wedged his axe here, blade facing outward, with the energy module constantly maintained in a preheated state.

After entering, he did not sit down, choosing the farthest of the three benches—from there, he could see everyone's face.

Vian arrived third. She brought a pot of boiled mint water from the Medical Station, a substitute concocted by dissolving the mint candies Lin Mo had given her into hot water.

She placed the pot in the center of the table, the spout pointing directly at the position where Lin Mo usually stood, and then walked over to sit on the bench opposite Locke.

The two were separated by a table full of maps and a preheating laser axe, but as she sat down, Locke quietly turned the handle by half an inch. It wasn't to guard against her, but to ensure she wouldn't have to navigate around the axe blade when she entered.

Alice arrived last. She held three strips of medical tape covered in writing—summaries of ship-borne Chaos combat files salvaged from the crash wreckage.

She laid the tape strips out on the table: the standard organization of the Chaos raiding fleet, the combat sequence of a Bishop-class Chaos Lord, and a typical attack schedule for the third wave, which she had reverse-engineered based on the Astral Knights' border records from the last five years.

On each strip of tape, at least three sets of numbers had been crossed out and rewritten, representing confidence intervals corrected after cross-referencing different data sources.

The annotations next to the numbers were standard coded abbreviations of the Astral Knights, and she had not translated them into Low Gothic. There was no need. No one in this room needed military terminology translated into plain language.

Once everyone had arrived, Lin Mo closed the door to the assembly room. The sound of Old Tom's forging hammer came muffled from the other end of the workshop, like distant rolling thunder.

He stood firm before the wargaming table, offering no opening remarks, no pep talk, and directly pushed the first iron filing onto the marker for the Salt Flats.

"The reconnaissance team's departure time is moved up to dawn tomorrow." His finger pressed down on the iron filing. "Direction: due north. Mission: confirm the actual scale and garrison strength of the signal relay station in the Salt Flats. Do not rely on signal calculations; I want it seen with your own eyes. Yang Shitou, have the people been selected?"

"Selected. Zhao Laonian and Liu Xiaoman." Yang Shitou turned the communication records to the last page, where the service summaries for the two had been copied in advance. "Zhao Laonian has been running reconnaissance in the swamp area for three years and can squat in the mud for twelve hours without moving. Liu Xiaoman can distinguish waveforms—he doesn't read much, but his ears can discern the frequency difference between Chaos tactical encryption and Imperial standard encoding, within 0.03 percent, faster than my spectrum analyzer."

"Liu Xiaoman?" Locke shifted on the bench, the axe handle grinding against the notch with a faint metallic sound. "The kid who fell from the watchtower while dozing off during the night shift, breaking two ribs?"

"He broke two ribs, and three months later, he was back at the watchtower." Yang Shitou pushed the file forward an inch. "When he fell, he was still clutching the communication logboard. The board wasn't damaged because he'd cushioned it against his chest when he hit the ground. Lord Locke, that wasn't dozing off. He had been on night shift for three consecutive days, tracking a set of frequency-hopping signals—he'd discovered them himself and hadn't reported them because he wasn't sure. The first thing he asked when he woke up was whether that set of signals was still there. The Deputy Medical Officer can testify to this."

Vian nodded. "I handled the admission. When he was wheeled in, he still wanted to sit up from the stretcher. His lips were completely white, and the moment he opened his mouth, he asked, 'Is that frequency hopping still there? The frequency hasn't changed, it just hopped to a backup band. Please, go to the communications station and take a look for me, just one look.'"

Locke was silent for a moment, then flicked the leather sheath of the axe handle—this was his sign of approval. "Good enough. Both are good enough."

"Then those two it is." Lin Mo moved his finger away. "Reconnaissance gear: portable spectrum analyzer, manual silent beacons; do not activate active signals on the communication relay at any point. Reconnaissance duration: three days. If they don't return after three days—" He paused for a beat. "We will not send a second team. The frontline defense deployment remains unchanged."

The room was silent for a long while. No one objected; everyone went through the logic in their minds: if they didn't return in three days, they were either captured or had discovered a key target and gone into hiding voluntarily. Either way, sending more people would only expose more. Lin Mo had said "do not send people," not "do not look for them"—the former was an order, the latter was a tacit contingency. There were no lies in his orders.

"Second item." Lin Mo pushed the second iron filing onto the swamp marker on the perimeter of the city wall. "Wargaming conclusion: the main attack direction for the third Chaos wave is not the Salt Flats, nor does it look like the swamps. Alice, you explain."

Alice stood up and walked to the side of the map—she didn't stand next to Lin Mo, choosing a position where everyone could see both her and the map simultaneously. This was the standard stance for an intelligence officer of the Astral Knights to give a briefing.

"The third Chaos wave is a full-strength raiding fleet, including three to five heavy cruisers, each carrying at least a battalion of Chaos Marines, with a total strength of two thousand to two thousand five hundred men." She pointed at the first set of numbers on the tape. "This Bishop-class Lord is a follower of Khorne and prefers frontal assaults; he will not disperse his forces. He will concentrate all his troops on a single landing point, using successive waves to strike the same section of the defense line. According to five years of contact records at the border, the tactical template for a Chaos Bishop attacking a single section of a wall is quite fixed: the first wave is a light assault to exhaust ammunition, the second wave is heavy mechs for a pinpoint breakthrough, and the third wave—the Bishop himself takes the field."

"If it were me," Lin Mo pointed with the end of his pen at the narrow passage between the swamps and the city wall, "I wouldn't choose the swamps. Heavy mechs are too restricted in the swamps. I would choose here—the hard-packed dirt plains outside the East Wall."

Alice shot him a sharp look, half a beat faster than usual.

"Correct. The mine density in the swamp area is already one every five steps. Followers of Khorne don't fear death, but they don't like meaningless death. Being blown to pieces by mines in a swamp is slaughter; charging a wall on hard ground is combat." Lin Mo switched the pen to his other hand. "So he won't come to the swamps. He will use the relay station in the Salt Flats as bait, making us think the main attack is in the swamps, while the real heavy forces are fully pressed against the East Wall."

Locke stood up and walked to the map, pressing his thick, heavy finger onto the East Wall marker, with enough force to leave an indentation in the paper.

"The East Wall is the weakest section." His voice was heavy. "Two months ago, an orc raid loosened half the foundation. Old Tom and his team spent two months repairing it, and they did, but the repaired parts are still thirty percent weaker than the original wall structure."

"Thirty percent—can it be held?"

"Depends on how long."

"Four days. Four days at most."

Locke withdrew his finger and slowly drew a line across the terrain from the East Wall to the swamps. "Distribute half the mines from the swamps to the outside of the East Wall. Regardless of whether Zhao Laonian's reconnaissance team returns, the deployment at the East Wall remains unchanged. I will defend the East Wall; give me three hundred men."

"Two hundred." Lin Mo said.

"Two hundred and fifty."

"Two hundred. Of the three hundred you want, one hundred must be allocated to the reserve—not for you, but for Alice."

Locke glanced at Alice, then turned his gaze back to Lin Mo. "The reserve is under her command?"

"The reserve won't be under anyone's command; it will simply be placed within the coverage of her psychic perception. The Chaos Bishop will take the field personally; his psychic level is at least six. Alice's psychic barrier needs to cover both the middle section of the East Wall and the reserve assembly area simultaneously. If she is distracted by command, the barrier will leak. Once the barrier leaks, the Bishop will be able to tear open the East Wall on the spot." Lin Mo's voice was very low, laying out the conclusions he had derived from three solitary wargaming sessions in the early hours, without reservation.

Alice stood by the map, tapping her fingertip lightly on the tape without speaking. Vian noticed her fingertip paused for a long time, as she was comparing Lin Mo's deployment against her own simulations point by point. A moment later, she looked up at Lin Mo and nodded slightly. This nod was extremely subtle, but by the standards of the Astral Knights, it was equivalent to a signed tactical approval.

"Vian." Lin Mo turned to the other side of the table. "You go to the observation post on the city wall, the same position Locke mentioned to you last time, and be responsible for artillery calibration. Besides that—you must keep a close watch on the swamp direction."

"Isn't the swamp a feint?"

"It is a feint. But if a feint isn't watched, it will become a real attack." Lin Mo pushed the third iron filing to the midpoint between the swamps and the East Wall. "The Bishop will detach a secondary force to probe the swamps, not many troops, two or three hundred. But if there is no counterattack from the direction of the swamps at all, he will push his reserves directly into it. So, someone must be nailed down there."

"How many people?"

"Fifty men, plus Old Tom's tripwire mines. I don't ask that you hold it, only that you stall them. Stall them until the battle at the East Wall is over."

Vian calculated it in her mind. Fifty men stalling two or three hundred—it wouldn't rely on firepower, but on mine density and terrain. She nodded, just like Alice, the nod so light it was like a single syllable.

"Yang Shitou." Lin Mo turned to the communications soldier. "For the signal deployment over the next seventy-two hours, three things. First, maintain full-spectrum silence, do not move the beam directed at Terra. Second, every time the interval of the unknown echo shortens, record the exact time, frequency, and intensity. Third—" He pulled out a folded piece of paper. "If Terra receives an automatic confirmation receipt after fifty-one hours, you reply using this code."

Yang Shitou took the paper. It contained a set of mixed codes he had never seen before: Low Gothic roots compressed into single bytes, with all articles and prepositions deleted, leaving only bare content words plus numerical coordinates. This format was not in the Imperial communication regulations, but Yang Shitou saw the benefits at a glance: for the same amount of information, transmission time was reduced by sixty percent, and the difficulty of deciphering it after interception was increased by at least an order of magnitude.

"You wrote this yourself?" Yang Shitou looked up.

"Wrote it in the early hours. Based on the Imperial exploration fleet positioning code structure Vian gave me, using the logic of root compression in reverse." Lin Mo said. "If there's no receipt after fifty-one hours, it's not a distance issue. Send it again using this code. If there's still no receipt after two attempts—" He paused. "Then it's not that someone is intercepting it. It's that Terra's communication array is no longer where we think it is."

No sooner had he finished speaking than the sound of a forging hammer exploded outside the window. Old Tom's first hammer blow this morning was at least an hour earlier than usual—he was rushing the work. He had heard about the war council from Xiao Zhou last night and had lit the furnace before dawn.

"Regarding Old Tom," Lin Mo looked out the window, "what is the progress on the tripwire mines and springs?"

"Last night he lowered the quenching temperature of the last batch of fuse springs by eight degrees." Xiao Zhou appeared at the door, not daring to enter, and only handed the production log through the crack in the door. "He said that at a temperature eight degrees lower, the fatigue life of the springs could increase by forty percent. He didn't say anything else, but this morning he baked three springs on the furnace to test the hardness curve."

Lin Mo took the log. On the blank space at the bottom of the last page, three spring cross-sections were drawn in charcoal, with the quenching temperature and tolerance range marked next to each. At the very bottom were Old Tom's crooked words, each stroke looking as if it had been hammered onto an anvil: "Fuse tolerance ± 0.01. If it's not within this number, don't install it on my mines."

Lin Mo returned the log to Xiao Zhou. "Tell Old Tom that the mine density outside the East Wall will be half-distributed from the swamps, doubling the quantity, but the tolerance cannot be lowered."

"He'll definitely agree." Xiao Zhou took the log. "When he agrees, he never says 'okay,' he just quenches the springs right away."

"That's enough."

Xiao Zhou ran back to the workshop, and the sound of the forging hammer rang out again, denser than before. The rhythm was three light strikes and one heavy—Old Tom was adjusting the temperature of the quenching pool. Once it reached the degree he was satisfied with, he would quench the entire batch of springs for the day—no eating, no drinking, working until dark when the furnace fire went out.

Lin Mo faced the wargaming table again, returning all three iron filings to their positions: one in the Salt Flats to the north, one on the hard-packed dirt plains of the East Wall, and one at the midpoint between the swamps and the East Wall. In the morning light, the three iron filings cast three extremely thin shadows, all aligned with the direction of the window.

"Deployment summary." His hand hovered over the iron filings. "Reconnaissance team: tomorrow at dawn, Zhao Laonian and Liu Xiaoman to the north. Main defense line: East Wall, Locke with two hundred men. Reserve: Alice's psychic barrier covering the middle section of the East Wall. Artillery calibration: Vian at the observation post. Swamp feint direction: fifty men plus tripwire mines. Full-spectrum silence: Yang Shitou to keep a death grip on the changes in the unknown echo."

He paused. The forging hammer outside the window happened to stop for a beat—Old Tom was changing the spring steel.

"Everyone remember three things. First, the Chaos Bishop will come personally; his arrogance will not allow him to stay on the ship. Second, his main force will be concentrated on one point—the East Wall. Third—if at any moment after the battle begins, a third type of signal appears from the north—not Chaos, and not ours—" His gaze swept from Yang Shitou to Locke, then landed on Alice. "—that is the reason we sent the reconnaissance team to the north."

"What is that?" Locke asked.

Lin Mo didn't answer directly. He pulled a fourth iron filing from his pocket, a size larger than the first three, with a mark from pliers on its surface. He placed this iron filing at the northernmost end of the map.

"Before Zhao Laonian returns, keep the defense line held."

Locke looked down at the map, his fingers tracing an arc in the air over the clearing between the shadow of the Eastern Wall and the swamp—not on paper, but in the air. His hands were rough, yet the arc was smooth. This was his habit in warfare: look at the terrain first, calculate the men at his disposal, and finally decide where to bet his life.

"Four days," Locke said. "You said, at most four days."

"Correct."

"And after four days?"

"If Terra's receipt hasn't arrived after four days, we'll have to rely on ourselves." Lin Mo set his charcoal pencil on the edge of the map. "But if Zhao Laonian can bring back good news on the third day, we can figure out the Bishop's troop composition and the actual scale of the beacon in advance. If we know in advance, four days is enough; if we don't, four days won't be enough. Therefore, the scout team must depart no later than dawn tomorrow."

Alice walked over from across the table, stopping at a distance where she could look him straight in the eyes.

"Have you considered a possibility—that the third wave arriving in less than two weeks is based on the Astral Knights' archives' average. But we annihilated his patrol and intercepted the encrypted reply; he has been provoked." She tapped the number on the tape that had been circled three times. "Arrogance will make him speed up. Not two weeks, maybe ten days, or even shorter."

Lin Mo glanced at her. "You didn't mention that at the meeting just now."

"I didn't say it because I needed to first confirm whether your deployment could be implemented within ten days." She paused. "It can."

"What is the basis for that?"

"The basis is that moment when you pressed that code onto the table without saying it. You were buying time for everyone. I didn't need to expose that at the meeting."

Vian watched the two from the other side of the table. Alice didn't look at her while saying these things, but Vian knew she didn't need to. A brief eye contact at the Intelligence Center last night had already confirmed each other's stance. The trust between two Psykers does not need to be confirmed every day—exchanging a glance at a critical moment is enough.

Locke pulled his axe out of the notch in the doorframe. The axe blade cut a blue-white arc in the morning light, sweeping across the ceiling of the assembly room like a severed signal wave.

"I'm going to the Eastern Wall. Starting today, the Eastern Wall sentry posts will be doubled, and the shift interval will be reduced from four hours to two hours. Have everyone walk the Eastern Wall foundation until they know it by heart; they should know which section is newly repaired even with their eyes closed. Arrange the recruits in the bunkers inside the outer wall; they will be afraid when the fighting starts, but the bunkers are thick enough to withstand the first wave." He walked to the door, paused, and without looking back, said, "Deputy Medical Officer, the observation post is on the roof of the Arsenal; it can see the entire Eastern Wall section and the swamp entrance. I'll take you up there this afternoon."

Vian stood up. "You won't be at the Eastern Wall this afternoon?"

"I'll be there in the afternoon. But taking you to identify the observation post is more useful than stacking another layer of sandbags." Locke walked out after saying this. His footsteps were heavy, yet he paused for a beat at the door—Xiao Zhou was standing outside, holding a freshly quenched spring, the oil on it not yet wiped clean, shimmering with a dark blue light in the morning sun.

"Lord Locke—" Xiao Zhou held the spring higher. "Old Tom says the foundation of the newly repaired section of the Eastern Wall has a bite interface that is thirty percent weaker. If you are going to station men on that wall section, he can add a layer of spring backing plates on the inner side of the wall, using the scrap from the tripmines, enough to make forty pieces. Each piece can disperse a quarter of the artillery shockwave."

Locke looked down at the spring and gently rubbed his finger pad against the surface. The dark blue oxide film of the quenched layer made a very faint friction sound under his rough finger pad.

"Tell Old Tom for me that the springs he quenches are of better quality than the Imperial Arsenal." He thought for a moment and added, "Also tell him, after this battle is over, I'll treat him to a drink. Not ale, but the high-proof whiskey I've stored for five years at the border."

"Old Tom doesn't drink." Xiao Zhou scratched his head. "He says a blacksmith's hands will shake if he drinks."

"Then treat him to tea. Use that tea set he brought from the Empire."

"That tea set of his was brought from Terra, he doesn't let anyone use it."

"You tell him it's my treat."

Xiao Zhou ran back to the workshop. The sound of the forging hammer didn't ring out immediately—Old Tom was listening to his reply. About half a minute later, the hammering resumed, the rhythm changing from rapid to steady, the interval between each hammer blow almost perfectly precise. Old Tom had found the quenching rhythm he wanted, and he would keep hammering until dark.

Lin Mo stood at the window of the assembly room. The morning light poured in completely, illuminating the map spread out last night in vivid detail. The shadows of the swamp, the markings on the Eastern Wall, the dashed line at the northernmost point he had added just before dawn—every line had nowhere to hide in the light. He had marked the true north direction using crystal refraction last night, and today he drew this dashed line on the operational map. He didn't tell anyone what this line meant, but as the meeting dispersed, he noticed that before Alice left, she gently swept her fingertip over the dashed line—no hesitation, no questions, just confirming that it really existed.

Yang Shitou was the last to leave. He tucked the communication records into the inner pocket of his combat suit and looked back at Lin Mo when he reached the door.

"Lord Lin Mo, the beam towards Terra, if no receipt is received after fifty-one hours, I will send the second set of codes exactly at fifty-two hours, not a second off."

"Not a second off? How do you guarantee that?"

"I tied the calibrator to the terminal, manually set the calibration pulse to once every 0.5 seconds, and automatically calibrate the beam direction every half second. As long as the antenna isn't blown up, the delay of the second set of codes won't exceed 0.5 seconds." He paused. "Is a 0.5-second error within a 51-hour communication cycle sufficient?"

"It's enough. It exceeds the standard precision of the Imperial Department of Military Affairs by ten times." Lin Mo looked at him. "Do you have a backup of your calibration records?"

"Yes. I copy one each night, put it in an iron box, and bury it under the trapdoor of the communication station floor. Stones block water, oilcloth blocks moisture, and Old Tom even welded a layer of lead sheeting outside the iron box for me."

"Lead sheeting—what are you defending against?"

Yang Shitou was silent for a long while. He pushed the calibrator eyepiece onto his forehead, revealing his left eye which had a red mark pressed into it. "Defending against that unknown echo. Its frequency can penetrate iron; it will reflect a part when passing through, but at least it won't contaminate my backup." He paused. "I gave it a name, unofficial, just for my own reference. I call it 'Echo X'. X is not a Roman numeral, it's the unknown variable in mathematics."

"What is the interval of Echo X now?"

"Forty-seven minutes." Yang Shitou flipped to the latest page of his notebook. "Compared to last night, it's shortened by nearly thirty percent."

"It is approaching."

"Yes." Yang Shitou closed the notebook. "And it is accelerating."

Lin Mo stood at the window, the morning light casting parallel shadows on the soundproof panels. Outside the window, the torches on the city wall were being handed over in the morning breeze, the night shift replacing the morning shift. Someone shouted "Handover complete," and the sound was quickly swallowed by the sound of the forging hammer. In the direction of the Eastern Wall, Locke was already leading people to stack sandbags, his voice loud enough to be heard across half the Arsenal: "Don't stack the sandbags flat, you need an angle, the angle can deflect artillery shells!" He wasn't yelling; he was teaching. When a recruit ran by carrying a sandbag, he would grab the slowest one, press down on his shoulder, and teach him to feel the correct angle.

In the square, Vian was walking toward the observation post. She stopped for a moment when passing the entrance of the Arsenal—Xiao Zhou rushed out of the workshop, clutching a handful of freshly quenched springs, almost bumping into her. The springs scattered all over the ground, and Xiao Zhou squatted down to pick them up, revealing all the burn marks on the back of his hands. Vian also squatted down to help him pick them up, and their hands touched amidst the quenching oil and dirt; she didn't pull back, but Xiao Zhou did. It wasn't that he was afraid of her, but that he was afraid the oil on his hands would dirty hers.

"Your burns need to be medicated," Vian said.

"They've been burned for three months, burned every day, I'm used to it." Xiao Zhou stuffed the springs back into his pocket. "Deputy Medical Officer, is there any medicine that I can apply and then continue blacksmithing? Something that doesn't need bandaging—once bandaged, it burns painfully when near the furnace."

Vian looked at the burn marks on the back of his hands, where new injuries were layered over old scars, and took out a small jar of beeswax-based burn ointment from her medical kit—not an Imperial standard issue, it was something she had formulated herself in Blackstone Town. "This doesn't need bandaging. Apply it and wait half a minute for it to dry; it will form a thin film that can last for four hours in front of the furnace. It needs to be reapplied after four hours."

Xiao Zhou took the jar and turned it around in his palm. "Four hours, that's enough. Old Tom said he'd give me half a day off after the battle."

"What do you want to do with half a day off?"

"Sleep." Xiao Zhou thought for a moment. "Then go to the communication station to find Yang Shitou. He said he wants to teach me to recognize the basic waveforms of spectrum diagrams, saying that my blacksmith hands can feel a spring tolerance of 0.01 millimeters, so my ears must be able to hear a frequency difference of 0.03 percentage points. He said he'd teach me after the battle."

Vian shoved the jar into his hand and stood up. Watching this teenager with hands full of burn scars run back to the workshop, the sound of the forging hammer immediately became denser. She stood there listening for a while before continuing toward the observation post.

A strange buzzing sound suddenly came from the direction of the communication relay station—not a calibration pulse, not a signal receipt, but the alert sound of the antenna suddenly locking onto a signal source in automatic tracking mode. Yang Shitou pressed the mute button to cut off the buzzing and looked down at the terminal screen—the interval of Echo X had shrunk again. Not forty-seven minutes, but twenty-one minutes. And on its frequency base, a second layer of modulation wave was being superimposed, a modulation method Yang Shitou had never seen before. It neither looked like chaotic permutation sequences nor Imperial positioning codes; it was more like a Q&A—the arrival time of each echo fell precisely into the fixed interval after the previous set of calibration pulses was sent. Seven seconds, nine seconds, twelve seconds. It wasn't random; it was a pattern.

Yang Shitou didn't write this into today's public record. He wrote it on the backup page of the iron box, the pencil writing very light, needing to be close to see clearly. After writing, he flipped to the next blank page and suddenly stopped. He wasn't sure if he should report it to Lin Mo immediately—not out of fear, but because he wasn't sure if Lin Mo still had the spare energy to receive a signal that couldn't be explained for the time being.

After thinking for a moment, he put the backup record back into the iron box, wrapped it in oilcloth, and stuffed it back under the trapdoor in the floor. He then sat back at the console and clipped the calibrator eyepiece back onto his eye. Calibration every 0.5 seconds, perfectly precise. He couldn't let a 0.3-degree deviation eat up one percentage point of signal strength. His fingers gently turned the frequency fine-tuning knob by less than a millimeter—the main beam was aimed at Terra, while the side lobe direction of the antenna happened to cover the location where Echo X appeared each time. It wasn't a coincidence; he had adjusted it on purpose. He was actively monitoring that thing. He named it X, and this time, it wasn't about the unknown variable in mathematics; he wanted to use the 0.5-second calibration pulses to grind away the outline of the unknown variable, inch by inch.

At noon, the sun shone directly on the city wall. Locke walked from south to north on the Eastern Wall, and then from north to south, marking every crack in the wall with a charcoal pencil. On the newly repaired foundation, he drew a circle with a vertical bar inside—this was his symbol for marking the "weakest point." After finishing, he turned around; the recruits were stacking sandbags behind him to build bunkers, the height already exceeding the parapet, each layer staggered at the angle he had taught. When a recruit's angle was off on the third layer, Locke didn't yell; he took the sandbag, corrected it himself, and then let the recruit put his hand on it to feel the correct angle. His teaching was never based on yelling; it was about letting the recruits remember the correct feeling with their hands—there is no time to relearn during a battle; one can only rely on muscle memory.

In the afternoon, Vian stood on the observation post for the first time. The roof of the Arsenal was scorched hot by the sun, and she could feel the temperature of the stone slabs through the soles of her leather boots. She lay behind the sandbags, scanning the entire section of the Eastern Wall and the swamp entrance with the range-finding telescope modified by Old Tom. The telescope mount was welded from scrap spring steel, and it made a slight metallic friction sound when adjusting the height. She spent the entire afternoon marking the coordinates of every terrain undulation outside the Eastern Wall on medical tape—rocks, dwarf shrubs, dried-up drainage ditches, every place that could hide a person was not missed. After finishing, she looked up and saw Locke looking up at her from under the city wall. His laser axe was resting on the sandbag, the blade reflecting the setting sun. He looked up for a long while, then knocked on the city wall three times with the axe handle: once, twice, three times.

She didn't understand the meaning of this signal, but she noted it down on the blank space of the tape.

At night, Lin Mo spread the map out again in the assembly room. The morning light was replaced by the dim yellow of an oil lamp, and the sound of the forging hammer outside had stopped—Old Tom had hammered for an extra half hour after dark today, the furnace fire had just gone out, and the workshop iron door was still radiating residual heat. Lin Mo rearranged the three iron filings, not in the order of deployment, but in the order of the Chaos Bishop's decision-making: where to look first, where to strike first, where to ignore first. He put himself in the Bishop's shoes, re-deduced it using the logic of a follower of Khorne, and then added another iron filing at the position of the Eastern Wall.

The fourth one. Unlike the previous three, this one had been warmed by his palm, and when placed on the paper, a faint circle of moisture would bloom around it, forming an almost invisible circle at the position of the Eastern Wall.

He wrote a line on the paper, the handwriting very light, needing to be brought close to the oil lamp to see clearly:

From Echo X to the beacon relay, from XV-091 to the dashed line of true north—all the pieces on the chessboard were falling into place according to the rhythm of the Chaos Bishop. But as long as he hadn't discovered the key to true north, he would think he was playing chess. He didn't know that he was also a piece. And this chessboard was drawn by the Emperor ten thousand years ago.

The mirror of the emperor did not light up. It was waiting. Waiting for Lin Mo to finish the last step of the deduction—not a deduction of certain victory, but a deduction: even if the Eastern Wall is lost, there is a second line of defense; even if the second line of defense is broken, there is a third choice. In a product manager's risk modeling, there is never "certain victory," only "what cards are left to play in the worst-case scenario."

After finishing the flowchart for the last backup plan, he leaned back in his chair. In the night sky outside the window, the three satellites had all passed their zenith. A few more hours and it would be dawn; the scout team would depart at dawn, heading north all the way.

Every strike of the forging hammer in the morning light—

was not about making landmines, but about buying time for the Imperial bureaucrats that they would never understand.

And the dashed line towards true north was, at this moment, only on Lin Mo's personal operational map.

But it was already closer to the truth than the Chaos beacon, Terra's silence, and the numbness of the entire Eastern Star Sector.