"Simply increasing the running distance isn't enough—or rather, the purpose of this special training wasn't to make you run farther in the first place."
Revisiting the training schedule, Yasui Makoto approached the wall and opened his backpack, explaining as he went:
"It's actually designed to enhance vertical displacement, body coordination, and control over your center of gravity and power."
"That's why in the next phase of training, how far you manage to run along the wall is actually secondary."
"The crucial thing is whether you can run exactly as instructed."
As he spoke, Yasui took out various training equipment from his bag.
"Put these on first."
"These are…?" Kitasan Black obediently leaned in, curiously inspecting what Yasui held in his hands, unconsciously voicing her question.
"As you can see—helmet, padded suit, knee pads, elbow guards, wrist guards."
Casually explaining, Yasui Makoto placed a helmet equipped with ear-shaped extensions onto Kitasan Black's head.
"I've told you before, real Extreme Acrobatics, whether in training or performances, always carries some risk."
"Take the 'horizontal wall run,' for example—in an official performance, there are required movements during the run itself, sometimes even at takeoff and landing, especially landing maneuvers."
"Although you won't be practicing those complicated moves, the height and trajectory you'll be running this time will be significantly more complex than before."
"You'll likely fall quite a few times in the beginning, so protective gear is a must."
"And there's also this."
After helping Kitasan put on all the protective equipment, Yasui Makoto pulled a thick stack of plastic material from the bottom of his bag, along with something resembling a blower.
Under Kitasan's curious gaze, he laid out the plastic at the base of the wall and connected it to the blower.
With a loud hum, the plastic expanded into a cushioned mat more than a meter wide and six or seven meters long.
When Yasui had first mentioned changes and possible risks in the special training earlier, Kitasan Black hadn't thought much of it.
Now, standing fully armored from head to toe, seeing the thick cushioning, she gradually understood just what level of change—and danger—he had meant. Nervousness crept in without her realizing it.
She touched the strap beneath her chin, felt the padded suit around her waist, glanced down at the cushioning beneath her feet, and was about to speak—when she noticed Yasui Makoto already scribbling marks on the wall with chalk.
"In general terms, the Japanese Derby seriously tests both explosive power and stamina," Yasui Makoto said, marking different heights and glancing toward Kitasan. "This requirement stems directly from the racecourse's distinctive 'multistage undulations.'"
"Immediately after exiting the gate, there's a lengthy downward slope with an elevation drop of 1.9 meters, continuing for quite a stretch, followed by another continuous half-meter descent."
"Before entering the third corner, there's a 1.5-meter incline, with yet another half-meter descent halfway through the turn—though this time it's considerably steeper."
"Just before the final corner, it turns upward again—a lengthy slope with a height difference of 2.4 meters, after which is the final straight."
"Compared to other courses, the Derby's slopes might appear mild, but the cumulative elevation difference of over five meters throughout the race significantly drains your stamina."
"And due to these segmented undulations, if adjustments aren't made promptly, your pacing can easily fall apart, leading to exhaustion near the end."
"So, you should now understand why I said your earlier training wasn't sufficient."
With Yasui's explanation, the wall had become dotted with marks, high and low.
Staring at these markings, Kitasan Black felt even more anxious.
In her previous horizontal wall-running exercises, no matter how far she went, her path had always traced a smooth parabola.
Yet, judging from Yasui's markings, the Derby's slopes were fragmented and uneven—impossible to casually glide across like before.
At the same time, she clearly understood now exactly what Yasui Makoto meant by "difficulty."
If she practiced these slopes on flat ground—whether uphill or downhill—she wouldn't have to worry about height differences at all. She could simply run through them like she'd always done.
But isolating these differing vertical heights and attempting to tackle them all at once was definitely impossible.
Any slip-up would naturally send her tumbling off the wall; without the protective gear on her body and the cushioning on the ground, she'd definitely get hurt.
However, after a moment of anxiety, she came to a certain realization.
When she first began Extreme Acrobatics, Yasui Makoto had told her that if one could treat a vertical, straight-up-and-down "road" as if it were flat ground, then actual flat ground—no matter how steep the slope—would become much easier by comparison.
Clearly, the subsequent training was built upon exactly that logic.
The slopes of the Japanese Derby were undeniably complex, but if she could handle these drops and elevations on a vertical wall, then the real racecourse would certainly be manageable.
"…Let's get started, Trainer."
She tightened the wrist guards and rotated her joints slightly, looking toward Yasui Makoto.
"I already said, I'm completely ready."
Originally intending to give further instructions, Yasui unconsciously smiled upon hearing this.
"OK. Then let's start from the height of 1.9 meters. The requirement is simple: reach that height on the wall in the shortest possible time, and stay there as long as you can."
After concisely explaining the task, he stepped back a few paces and raised the timer.
In that instant, Kitasan Black assumed her running stance, her tail swishing straight upward and then falling back down.
This was the small habitual movement she always made during special training or when waiting in the gate—but this time, her imagined opponent wasn't any Uma Musume, but the towering wall in front of her.
"Well then…begin."
Seeing the girl ready, Yasui nodded and pressed the stopwatch.
With a short run-up, at the exact moment her foot struck the wall, Kitasan Black immediately grit her teeth.
She hadn't expected that simply adding a height requirement would drastically increase the difficulty of this familiar training.
On her first attempt, she completely failed Yasui's requirement.
She watched helplessly as her foot landed just beneath the mark labeled "1.9 meters," a slight panic rising as she instinctively tried to adjust her height.
Yet vertical exertion was totally different from horizontal exertion; compared to the latter, the former gave her a strange sensation of losing control.
As soon as she noticed her toes twisting awkwardly against the wall, the thigh muscles closest to the wall spasmed, quickly turning into a sense of helplessness.
Instinctively twisting her waist and swinging her arms, her other leg desperately traced an arc, trying to find another foothold—but suddenly, the rough wall became slick and slippery beneath her foot.
She barely managed to shift her center of gravity before the world spun in front of her eyes. She felt the shoulder straps of her padding tighten sharply, and in the next instant, her back landed on the cushiony, inflated mat.
…Th-this counted as a failure already?
Just as she processed what had happened, blinking in a daze, she heard the helmet making a tap-tap-tap sound.
Then Yasui Makoto's face appeared upside-down in her vision, wearing an unfamiliar, wicked little grin.
"So? Didn't I tell you your training wasn't enough?"
Squatting above Kitasan Black's head, tapping lightly on her helmet, Yasui couldn't hold back his teasing remark. But immediately after, his expression turned serious.
"So, treat this as your first attempt—start again."
"Remember what I said: Extreme Acrobatics isn't about brute strength; it's about cleverly using every part of your body with ease and flexibility."
"This time, try adjusting the angle of your foot placement—pull inward slightly—and engage your ankle earlier when stepping onto the wall."