He had tested it many times in Panlong City, and back-calculating from the stars in the sky had always been remarkably accurate. Just as Xu Shichu had said, this congruence formula could calculate not only the trajectory of the Tianluo Star, but all Nine Stars of the Big Dipper as well.
Yet tonight there were neither stars nor moon. The night sky was like a blank canvas, severely testing He Lingchuan's skills.
Naturally, he dared not complain. Who could guarantee the night of the actual operation would be clear and starry? What if it happened to be overcast and cloudy like this?
Juju gave him a sidelong glance. Though a fire monster, his tone was icy. "Can you actually do this or not?"
*Whether I can or not isn't up to you to say.* He Lingchuan hushed him. "Keep quiet. Mental math was never my strong suit."
*If only Master Sun were here.*
"Fly back five zhang—yes, exactly—now descend. It should be right here!"
Under the watchful eyes of all three, the little bat in the air suddenly twirled and was swept sideways against its will, skidding more than a dozen zhang away.
"Huh?" Dong Rui steered it to stabilize, circled around, and flew toward that spot once more.
Once again, an unseen force repelled the little bat.
It quickly descended, returning to its master's side.
Dong Rui communicated with it briefly, then turned to He Lingchuan. "There seems to be turbulent airflow there. Any bird that gets close gets swept away."
Air currents often formed at high altitudes, and birds frequently used them to glide.
"Could it be right there?" He Lingchuan pondered. "Try approaching from a different direction."
This time, the little bat approached from the west. Sure enough, once it neared the area, the current swept it away again.
"This band of airflow is fifteen zhang—over forty meters—above the peak, but its diameter is at least several dozen zhang. Does that make sense?"
Juju mused, "Outside the Spirit Gathering Grand Formation's core, there's an additional whirlwind array? Why wasn't that mentioned in your intelligence?"
In the memories of Zaifu Kua, the Junior Director of the Directorate for the Palace Buildings, there had been no whirlwind array outside the formation core at all. "The Heavenly Palace probably added it later."
"It pushes away all unrelated objects. Otherwise, if a bird flew into it and smashed head-on, wouldn't that be awkward? It would expose the core's location, too." He Lingchuan let out a breath. "Birds run into air currents all the time, so they wouldn't think anything of it. Besides, the formation core moves constantly; it won't be here tomorrow. Of course, this is all just conjecture. We'd better confirm it."
"How do we confirm it?" Juju tilted his head. "Should I hurl a few big fireballs up there to test it?"
"Don't!" Juju's attacks always came with excessive noise and blinding light effects; He Lingchuan quickly stopped him. "Are you afraid people won't know we're hiding here?"
"You two can crouch lower." He was the local mountain spirit; what was wrong with shooting off a few fireworks into the sky for fun? Was that a crime?
Seeing Juju eager to try, Dong Rui couldn't help chiming in, "If you hit it, the Heavenly Palace will know. How are we supposed to launch a surprise attack after that?"
The fact that the Spirit Gathering Grand Formation's core was no longer concealed within the void was a strictly guarded secret of the Heavenly Palace. Regardless of how Juju had found out, it would almost certainly put them on high alert.
This mission was hard enough as it was; did they really need to crank up the difficulty right now?
Juju had already conjured a fireball in his hand, but at those words, he snuffed it out with a puff. "Then you tell me. What should we do?"
*So this fellow is only cunning, not truly clever.* Realizing this, He Lingchuan spoke up immediately: "You've overseen Mount Xu for over four thousand years. Can you influence the weather here?"
"Hmph." Even an ordinary mountain spirit could do that, and Mount Xu was his true body. Calling the wind and summoning rain here was second nature. "Child's play."
"Then bring down a hail shower. The finer the ice pellets, the better."
Dong Rui secretly gave him a thumbs-up. The creature was made of rock and fire and ought to loathe rain and water above all else, yet He Lingchuan was demanding he summon hail.
To his surprise, Juju offered no resistance at all. "No problem. It just rained tonight anyway." And the weather was cold.
Volcanic eruptions frequently triggered hail and rainstorms. Besides, as a grand demon of thousands of years, why would he fear a little rain?
He Lingchuan heard a clattering racket emanating from Juju's body.
Monsters of this kind didn't chant incantations with a mouth; instead, the rocks across his body collided to produce rhythmic clacks. It wasn't melodious, but it had the punchy drive of percussion.
The impacts sent micro-tremors through the peak, equivalent to an earthquake of magnitude three or four.
Of course, Juju knew better than to make too much commotion and alert the Heavenly Palace, so the tremors were confined to this short peak.
Then, like a human, he leaned forward in a bow to the heavens, extending his arms forward with palms facing up, cupping a pinch of grit in each hand.
With a whoosh, a gale swept through, instantly scattering the grit in his hands without a trace.
The wind blew with ferocious strength, nearly sweeping a person into the sky. The guards atop Tianji Peak scrambled to take cover inside the hollow of the Dao-Seeking Tree.
After a dozen breaths, the wild wind subsided, and tiny, hard pellets began to fall from the sky, rattling against stone and wood with a sharp pitter-patter.
A few struck He Lingchuan's face. Reaching up to feel them, he found cold, hard little ice granules that melted the moment his body heat touched them.
The hail had arrived.
According to Juju, summoning gales and downpours was simple, and egg-sized hailstones were even easier. In contrast, sustaining a steady shower of tiny ice granules barely larger than raindrops was the hardest to gauge and control.
If the force was too great, it would easily trigger the defensive array attached to the formation core.
He Lingchuan and Dong Rui tilted their heads to gaze up at the sky. "Notice anything strange?"
"Nope."
A quarter of an hour later, the hail stopped.
Dong Rui wasted no time, preparing to send the bat demon puppet into the air once more.
Juju shook his head. "No need. The volcanic grit I let the gale carry aloft is currently suspended right in the center of the turbulence, completely still. I can sense it!"
He had mingled tiny grains of sand among the falling hail, letting them descend toward the turbulent airflow. Because they were essentially tiny fragments of his own body, he knew exactly where they landed.
Such were the perks of being the local master of the land; others could only envy him.
He Lingchuan couldn't help snapping his fingers. "Splendid! My calculations were correct—the formation core really is there!"
Accurately determining the location of the formation core meant their mission was already a quarter complete—a tremendous breakthrough!
"The defensive array didn't activate either." Otherwise, the grit would never have landed inside the core. This confirmed their earlier hypothesis: objects too small and light falling in wouldn't be registered as an attack by the defensive array.
Although turbulent airflow shielded the core, the wind blew outward in every direction. Tiny objects like grit wouldn't necessarily be blown entirely away; after swirling around and colliding a few times with the hail, there was a slim chance they could pierce through the turbulence and tumble into the core.
"But with that turbulence around the core, how do you get close?" Dong Rui raised a question. "Do you have a way to break through?"
He Lingchuan rubbed his hands together. "We might need a magic artifact that wards off wind."
Solve problems as they appear. That was the whole point of a test flight.
Juju said immediately, "A trivial matter. I have a Wind-Fixing Pearl here, taken two thousand seven hundred years ago from a sorcerer I killed. Nourished by my spiritual energy, it has never lost its potency."
Overjoyed, He Lingchuan took it. The bead was only the size of a quail egg, speckled with tiny spots across its surface, lacking the lustrous sheen of a true pearl.
The moment the bead settled into his hand, the breeze blowing past them became noticeably feeble.
"You have to time when to bring it out," Juju warned him. "You can't keep wearing it the whole time, or the bat carrying you won't even be able to get airborne."
It was a Wind-Fixing Pearl, after all; how could winged creatures take flight without wind?
"Just one?" He Lingchuan said, dissatisfied. "We need at least two."
"..." Juju sorely wished he could swat him dead with a single slap. "Do you think these are cultured pearls, harvested whenever you want? If you put that Wind-Fixing Pearl in your hand up for auction, it would fetch at least ten thousand taels of silver!"
He Lingchuan chuckled mirthlessly. Ten thousand taels for a Wind-Fixing Pearl? This fellow sure had a big mouth. Unless someone had a very specific use for it, who would be stupid enough to spend that kind of money?
"One really isn't enough," he said earnestly. "Strictly from a technical standpoint."
Juju grumbled impatiently, "Then scrape some powder off it and make do!"
"...That works too?" *And you said it wasn't a pearl?*
"I've tried it, but the powder scraped from the pearl only lasts two shichen."
He Lingchuan breathed a sigh of relief. "That's plenty."
Powder was even better—lightweight and portable. But just how bored was this old monster in his spare time to have thought of grating powder off a Wind-Fixing Pearl?
"We also need to measure the radius of the turbulence." After all, once in the sky, they would be blind. If his timing with the Wind-Fixing Pearl was off, he and the bat would slam straight into the defensive array.
"Leave that to me," Juju said with supreme confidence. "I'll play around with it."
He was the local mountain spirit; he had all the time and energy in the world to test things by trial and error.
Since Juju had taken on the task, Dong Rui launched the little bat into the air again, sending it toward the formation core from various angles to measure its actual size. Naturally, they couldn't do it too frequently, lest they be detected.
The demon puppet took to the sky over a dozen times, taking more than two shichen in total.
"The thing is round," He Lingchuan concluded after numerous tests. "Including the peripheral airflow, the diameter is roughly thirty zhang."
Juju's job, then, was to measure the airflow's "thickness," allowing He Lingchuan to gauge exactly when to activate the Wind-Fixing Pearl.
Having recorded the measurements, the two made their way down the mountain.
This time, Juju led them down an alternate route, departing through a hidden ravine.
It was an underground channel carved over many years by a stream. Later, the stream had altered its course, leaving behind a subterranean ravine that was completely invisible when looking down from the mountain summit.
Reaching this spot, Juju suddenly came to a halt. "The grit has been cleared away."
He Lingchuan had been keeping track of time in his head, so he remarked, "Roughly two quarters of an hour." Strictly speaking, thirty-three minutes.
"The grit was tiny, so it probably wasn't swept by hand. More likely, a cleansing array triggered." He smiled. "Seems this array isn't that diligent either." The interval between each activation was rather long.
Just how many overlapping arrays had the celestial gods piled onto the formation core since then? In the memories of old official Zaifu Kua, none of these messy extra arrays had existed.
He Lingchuan suddenly remembered something and inquired of Juju, "By the way, has there been any unusual movement around Zhaixing Tower over the past few days?"
"None. Same as usual." Having guilty secrets of his own, Juju naturally kept an extra-close watch on the Heavenly Palace.
"Any uncommon figures visited?"
This time Juju thought for a moment before answering, "Oh, right. National Preceptor Qingyang came up the mountain this morning."
Chapter 670