The Principles of Force
Several months had passed since then. During meal times, Akasa would check the fruit and the fish traps, all while absorbing Urnil’s teachings and building the fruits of his training into his very body.
Focusing on the lead hand, the torso and hands rotate in opposite directions, causing the tip of the staff to alternate left and right.
Akasa’s rear hand pushed the staff forward, the tip striking the center of the tree with a crisp, clean sound.
Normally, one would simply advance for the strike, but the tree was too stoic an opponent. Akasa, considering the difference between an adult and himself, launched his now-agile body backward before leaping forward again.
He raised the staff high into the sky as he jumped, and upon landing, he brought it down so the entire length struck the ground simultaneously. A sharp, ear-piercing impact echoed across the grass-covered earth.
To defend his lowered posture, he raised the rear of the staff above his head, supporting the base with his other hand. This created a defensive stance capable of blocking intersecting lines. Furthermore, Akasa applied sudden pressure with his rear hand. The tip of the staff, which had been touching the ground, rose sharply to strike at the vital point of an imaginary enemy.
As the rear hand pushed forward, the sudden pressure caused the head of the staff, which had been resting on the ground, to soar. Akasa, like a crouching tiger, sprang forward toward the imaginary enemy—who was startled by the extended reach of the upward strike—and thrust the staff in a second time.
Thwack!
The thrust, backed by his full body weight, embedded itself into the tree.
[Good. The power itself is still lacking, but I can see you’re learning how to use your strength.]
“I think I’m finally starting to understand the sensation of using my hip joints.”
[The power behind the strike feels different now, doesn’t it?]
“Yes.”
Akasa retracted the staff and spoke with a voice full of respect. The way Urnil taught him was incredibly detailed yet efficient. Although he was young, he had learned the basics of martial arts and history as part of his royal duties. However, even those elites of the kingdom had never helped him experience the difference that comes from understanding the principles of training.
[If you grasp the structure of how the body rotates, you can understand the principles. The application might differ slightly depending on the weapon and the school, but in the end, it all comes from the human body.]
Previously, Urnil had explained the feet and hip joints.
[Akasa, see that sapling on the right? Go closer.]
Akasa approached with his staff.
[Hold the end of the staff, stand at the maximum distance, and try to push the other end against the sapling. Don't hit it. Just push while it's touching.]
Akasa did as he was told.
“Ugh.”
At first, he pushed lightly, thinking nothing of it, but then he strained with all his might. The weight and position of the staff in his hands were only enough to make the sapling, which was thinner than his own wrist, sway slightly.
[Now, move closer to the sapling while in that position. Keep it as close to your hands as possible and push.]
This time, it was easy. The sapling was pushed back sharply by the staff, which now had proper leverage, and it groaned with an unsettling sound as if it were about to snap.
[That’s enough.]
As Akasa stopped, Urnil asked, [You felt the difference, right?]
“It was hard when I was far away. It was easy to push when I was close.”
[Right. That’s the principle of the lever you already know. But instead of a lever, think of it as a center.]
“A center?”
Akasa wore a look of partial understanding.
[Does this tree have feet?]
“No.”
[What about a torso?]
Akasa straightened the sapling’s bent stem and replied, “It does.”
[Then you, who have feet while this tree does not, were unable to knock over a tree that is nothing but a torso?]
“Is that... how it works?”
Feeling embarrassed, Akasa stammered. Urnil laughed, a sound that resonated in his head, and said:
[Normally, I’d like to compare the roots to feet, but I’ll refrain from that analogy this time. It’s a bit different from the explanation I’m trying to give. Let’s call that upright body your torso, your spine. Then, let’s consider the roots below as the hip joints connected to your legs.]
“Yes.”
[Having roots firmly planted in the ground means your center is sunk low. Do you remember when we went to pick up the fish traps? How did you act because you thought you might slip?]
“I... lowered my stance.”
[And how was it?]
“It was much more stable, and I didn’t fall... Oh, I see!”
Akasa’s eyes sparkled as he spoke. “Because I’m sunk low and sturdy, I can withstand the opponent more easily even when I exert force, right?”
[If you can withstand it, you can also push.]
Akasa shifted his gaze from the bracelet to the sapling with a slightly different look in his eyes.
Because it had its roots firmly in the ground and held its center, even a small sapling could not be defeated by force applied far from that center. But conversely, if he applied the heaviness of this center to his martial arts, even Akasa, still just a child, could deliver a fatal blow to an adult.
[Usually, combat instructors tell soldiers to add rotational force with their feet and waist. But that won't give you decisive power when you really need it. The feet push the body to move forward. They determine direction and momentum. In martial arts, the center and rotation come from the hip joints. You must load the weapon you wield into this rotation to achieve destructive power.]
Akasa gripped his staff and took the basic thrusting stance he had learned toward the tree. Then, he thrust forcefully at the target tree.
The impact transmitted to his hands from the tip of the staff after a deep breath was far more powerful than before. He didn’t know what Urnil meant by always advising him to remember this specific thrust, but in this moment, Akasa could clearly feel the difference.
[Training for a precise thrust is difficult, but it’s far more powerful than swinging it like a child. As long as you have your center, you’re thrusting with the weight of your entire body.]
Furthermore, Urnil explained the structure.
[It’s not here, but have you ever seen a hammer used by a sculptor or a carpenter?]
“Yes.”
[Can you describe its shape?]
Akasa described it. He knew that Urnil, a god, wouldn't ask him something so obvious without a reason.
“There’s a wooden body, and a block of iron with flat ends on both sides attached to it.”
[Correct. Then why are there faces on both sides? You only hit with one side anyway.]
If the reason were simple, one might say it’s so you can use the other side if one breaks or gets damaged. But Urnil’s question was meant to help Akasa understand his training. In other words, it was an analogy for Akasa’s own body. Akasa couldn't handle this difficult question.
“I don’t know.”
Then, Urnil told him an old story.
[A long, long time ago, the first hammers only had one side. But they had to endure simple tasks, and the handles kept breaking.]
“Like an old man’s cane?”
[Exactly. That kind of shape. So, the blacksmiths thought: if the hammer keeps breaking, why not increase the weight so the work is easier even if you hit less often?]
Akasa looked down at the Karmatio with curious eyes.
[The blacksmiths added a lump of iron to the back to add weight. But the strange thing was, after that, the hammer handles stopped breaking while they worked. And the blacksmiths’ career longevity increased significantly. Originally, they retired early because they lived with chronic wrist pain. Do you know why?]
“...I don’t know.”
[Because it provided a path for the force to escape.]
“A path?”
[Let’s experience it firsthand from here. Experiments at the end of the story.]
Urnil said excitedly. Akasa prepared two types of branches as Urnil instructed. One was a branch that split only on one side at the tip, and the other was a branch that split evenly on both sides. Akasa trimmed the ends slightly so they could be used like hammers. Both were handles that weren't very thick.
Akasa said with a worried face, “They look like they’ll break if I give them even a little impact. Is this really okay?”
[You don’t need to use much force. We’re just finding out the difference in the two types of force. Hit it lightly.]
Urnil told Akasa to hit the two types of branches against a flat stone until he felt a slight impact in his hands.
[How does it feel?]
“Uh, I can’t really tell with just one hit.”
[Hit it more. You need to feel the difference, so keep the intensity of the force the same.]
Akasa, who had hit the stone while changing the intensity, said with a look of wonder:
“The branch with heads on both sides definitely has less impact. It’s amazing. Why is that?”
[Let’s draw a picture on the ground. Draw the two hammers. Make them look hollow, just the silhouettes.]
Urnil calmly guided Akasa.
Akasa drew on the dirt floor. He drew a hammer with one protrusion on a long stick, and a hammer with protrusions on both sides.
[When we hit something, the opposing force also enters our body. That’s called reaction force.]
“Reaction force?”
[When you thrust your staff at the tree, your body is pushed back because you can’t push the tree, right? That’s also an example of reaction force.]
“Ah, I understand.”
[Then, when you thrust the staff, there must be a force coming back to you through that staff. What is the shape of the staff?]
“It’s a stick, so it’s a straight line... right?”
[Right. That’s why the reaction force is transmitted directly to you. Now, let’s look at these drawings again.]
Akasa looked at the drawings with a face that suggested he was starting to understand. Urnil continued in a calm tone.
[Then, when you strike with a hammer, the reaction force will naturally come in from the hammer’s head. Can you explain how that force enters?]
Akasa drew the direction the force would flow with the tip of a branch on each hammer. The single-headed hammer’s force went straight through the handle, but the double-headed hammer had two paths.
After thinking for a moment, Akasa drew both the path leading to the opposite head and the path leading downward.
[Do you know what the difference is?]
“The one with one head returns the reaction force straight through the hammer body, but the two-headed hammer lets the force escape through the rear head. So, the impact returning to my hand is less!”
[Correct. But if I were grading your answer, I’d give it an 80. It’s a bit lacking.]
“What? Did I miss something?”
Akasa looked extremely disappointed, as his expectation of being praised for being clever had been dashed. Urnil laughed softly and said:
[Look at what you drew one more time. The single-headed hammer diverted the path, and the two-headed hammer flowed out through two paths, right?]
“Uh, yes.”
[Do you remember me saying the hammer broke?]
“Uh...”
Akasa opened his mouth after deep thought.
“Are you saying the force didn’t go around the path, but collided and bent inward?”
[Exactly. Force has no will. So it collides and runs only along the given path. That’s why if a faulty structure continues to receive and accumulate force, it eventually breaks. Martial arts are the same, and that’s the reason everything in the world has its own proper etiquette and form.]
“Proper structure...”
[Of course, what you’re most interested in right now is martial arts and training. You’re no longer a prince, but don’t be lazy about learning various structures. It will definitely help you.]
Like this, Urnil was sometimes strict, but at other times, he used materials found in the forest to build Akasa’s principles of training, his posture, and his character.
Like a baby bird being fed by its mother. That constant, calm attention provided Akasa with excellent emotional stability. However, Urnil knew. Even if he told him all this, the ways he could directly protect Akasa were extremely limited. Therefore, if a situation ever came where he truly needed to protect himself, it would depend entirely on Akasa’s own capabilities.
Akasa did not realize this.