On the tenth day after the battle, the wind and snow at Iron Wall Pass remained bitingly cold, but deep within the Formation Maintenance Camp, inside the "Spiritual Hub Hall," it was warm and cozy.

Su Ming stepped into the hall. Underfoot was warm, smooth jade paving, and the surrounding walls were inlaid with several fist-sized Moonlight Stones, illuminating the entire great hall with crystal clarity. The air was suffused with a faint, calming fragrance, a world apart from the crude barracks outside filled with the smell of iron and blood.

At the center of the hall, dozens of formation plate projections floated in mid-air, slowly rotating, emanating profound spiritual energy fluctuations.

Behind a desk carved from a single piece of cold jade sat an old man with hair and beard as white as snow.

He wore a plain robe without any rank insignia and was playing with a fragmentary rubbing of an ancient formation line in his hand. His gaze was focused, as if it were the most precious treasure in the world.

This person was precisely Elder Mo, the pillar of stability for formations at Iron Wall Pass, a great cultivator at the mid-Golden Core realm.

"Disciple Su Ming, greets Elder Mo." Su Ming performed a respectful bow, his expression reverent, neither subservient nor arrogant.

Elder Mo did not look up, his fingers still stroking the rubbing. With a casual wave of his hand, one of the formation plate projections floating in the air drifted before Su Ming.

This was a standard "Spirit Gathering Conversion Formation," but as the spiritual energy flowed through the core hub, there was always an extremely subtle pause, causing a full thirty percent loss in conversion efficiency.

"One incense stick's time. Find the crux of the problem." Elder Mo said lightly.

Su Ming did not rush to answer. Instead, he activated the *Like Water Art*, a faint layer of mist covering his eyes.

Under the "Observation Micro State" vision, the flowing spiritual energy within the formation plate was no longer a dull line but surging rivers.

"Master," Su Ming thought inwardly, "It looks like congestion caused by insufficient purity of the spiritual materials, but it's actually because the return flow pipe is too narrow, creating turbulent flow."

"Nonsense, this old man is testing you," Lin Yu's voice sounded in the Consciousness Sea, carrying a hint of teasing. "Don't be fooled by appearances. The structure of this formation is modeled after the human body's meridians. Use a guidance and channeling approach to solve it."

Su Ming understood. He did not reach out to touch the formation plate but extended a finger, pointing it in the air at the "Dui position" on the lower left side of the plate.

"The spiritual energy flow here is too fast, creating a counter-current with the return flow from the 'Kan position'," Su Ming said softly. "It's not an error in the formation line carving, but rather, when the spiritual energy passes through the right-angle turn, it creates a 'whirlpool,' hindering the follow-up spiritual energy. If we change this right angle to a curve, or add a 'water-splitting line' at the turning point, the problem will resolve itself."

Elder Mo's finger paused slightly.

He looked deeply at Su Ming, the corner of his mouth lifting in a barely perceptible arc. "Interesting. Not modifying the main formation, only repairing the auxiliary branches. Now look at this."

He waved his hand again, tossing out three consecutive fault cases. Each one was more tricky than the last. Some appeared to be spiritual energy depletion but were actually channel blockages; others seemed like attribute conflicts but were actually due to impure mediums.

Su Ming responded with increasing ease. He didn't speak of those profound and mysterious formation principles, only using the simplest "water method permeation" logic, treating spiritual energy as water flow—where it's blocked, guide it; where it's too fast, slow it.

After a quarter of an hour, Elder Mo set down the rubbing in his hand.

Elder Mo stood up and walked to a massive jade wall at the rear of the hall. On the jade wall was displayed a structural diagram of a core node of Iron Wall Pass's mountain-protecting grand formation.

"This is the 'Spiritual Pressure Buffer Hub,' the heart valve of the grand formation," Elder Mo said, pointing at an extremely complex structure in the diagram and sighing. "It's an old component from three thousand years ago. The design is outdated, and its spiritual energy throughput efficiency is extremely low. Every time a demon tide attacks, this place overheats due to overload, even risking explosion."

"Then why not replace it?" Su Ming asked.

"Can't be replaced," Elder Mo shook his head. "This hub connects to three main spiritual veins. Pull one hair, and the whole body moves. Once replaced, Iron Wall Pass's entire defense would be paralyzed for at least three hours. The Demon Tribe is right outside the pass, watching like a tiger. Who would dare take such a risk? If we try to forcibly modify the internal formation lines and cause a spiritual explosion through the slightest carelessness, I would be a sinner for all eternity."

This was a deadlock.

Change it, the risk is too great; don't change it, the hidden danger is endless.

Su Ming stared at the massive structural diagram, his brow tightly furrowed.

Su Ming did not answer immediately. He remained silent for a long time before slowly speaking, "Elder Mo, may this disciple go to observe the actual site for three days?"

"Granted." Elder Mo uttered a single word.

...

For the next three days, Su Ming seemed to have taken root beside that "Spiritual Pressure Buffer Hub."

He didn't dismantle a single screw, nor did he release even a wisp of spiritual energy to probe. He just held a blank jade slip, tirelessly recording.

He recorded the fluctuation curve of the spiritual pressure every hour, recorded the frequency of each tremor of the formation hub, and even recorded the faint whistling sound made when spiritual energy flowed through the pipes.

To others, he looked like an idiot meditating on a rock.

But in Su Ming's Consciousness Sea, Lin Yu was helping him construct a precise data model.

"See it clearly?" Lin Yu pointed at the node in the model that kept flashing red. "The biggest problem with this old hub is 'hard resistance.' It's like a wall, stubbornly blocking the returning spiritual pressure. What we need to do isn't to thicken this wall, but to dig a ditch beside it."