Blood Qi (Thanks to Big Fish ZT for the tip)

Facing his father's childlike, inquisitive eyes, Su Hao did not beat around the bush and gave the answer directly. "A blind man!"

"Why can't a blind man see a doctor?" Wu Yuntian looked utterly confused.

"Because a blind man can't see, so naturally he can't see a doctor." Su Hao explained helplessly.

Wu Yuntian remained silent for a long while after hearing this.

Su Hao could not help worrying that his father might be wondering whether he was an idiot!

Wu Yuntian and Su Hao sat cross-legged facing each other, one large and one small, the contrast stark.

After pondering like that for a moment, Wu Yuntian slowly said, "If you want to learn martial arts, you must first understand what martial arts are. Over the next half year, I will slowly teach you the fundamental principles of martial arts. Once you can skillfully control your body, we will begin training."

"Humans are different from Ferocious Beasts. The strength of Ferocious Beasts is an inborn gift, an instinct, but the strength of the Human Race is not. The Human Race relies on wisdom. During their long struggle against Ferocious Beasts, our ancestors discovered the secret behind their power: Blood Qi. Thus, our ancestors developed all kinds of Blood Qi training methods, allowing the Human Race to gain the strength to confront Ferocious Beasts head-on. Such Blood Qi training methods are called Blood Qi Secrets or Blood Qi Canons. Their functions are much the same, with little difference between them."

"As for what Blood Qi is..." Wu Yuntian paused here and looked at Su Hao, who was listening with rapt attention, seemingly considering whether his young son could understand such things at this point.

Su Hao looked up and asked, "What is Blood Qi?"

Wu Yuntian smiled self-mockingly and no longer hesitated. "Xiangwu, raise your hand."

Su Hao did as told and raised his hand.

Wu Yuntian asked again, "Tell me, why can you raise your hand?"

Without hesitation, Su Hao said, "Because when the muscles in the arm contract, they pull the forearm, and the hand rises."

Wu Yuntian did not ask why Su Hao knew such things, instead pressing on. "Why can muscles contract?"

Marble Space immediately searched up an article describing muscle contraction, but Su Hao knew that was not what his father was asking. Uncertainly, he said, "Because there is energy inside the muscles?"

Wu Yuntian approved of Su Hao's understanding of the concept of energy and nodded. "That's right. Not only do muscles contain energy, every part of our body possesses energy. With this energy, we can walk, leap, and grasp."

As he spoke, Wu Yuntian pointed at a basketball-sized stone in the distance. "Xiangwu, go move that stone over here."

At the sight of it, Su Hao's eyelid twitched. Looking at his own skinny arms and thin legs, he was not sure he could move it. Still, he said nothing. He got up and jogged over to the huge stone, first trying to hug it up, but failing. Then he went behind it, heaved it up with both hands, exhausted every last ounce of prehistoric strength in his body, and pushed the stone rolling to his father's side.

Wu Yuntian had Su Hao sit back down, then casually grabbed the stone and tossed it in his hand. "Is the stone heavy?"

Su Hao looked enviously at his father's thick, powerful arms and answered honestly, "Heavy."

"It is very heavy to you, too heavy for you to lift, but it is very light to me." As Wu Yuntian spoke, he tossed the stone. It traced an arc through the air and rolled back to where it had been. "Why?"

Su Hao was suddenly speechless. He had rolled that stone all the way over, thinking it would serve some special purpose, only for it to be tossed back? If he wanted to ask a question, why make him do such useless work? With no other choice, Su Hao obediently followed the train of thought. "Because my arms have little strength, while Father's arms have great strength. In other words, my arms have little energy, while Father's arms have more energy."

He did not mention age as a factor, because he knew that was not what his father was asking.

Wu Yuntian nodded. "That's right. My arms contain more energy, while your arms contain less. So let us give this energy a name: Blood Qi. Then we can say that the Blood Qi in your arms allows you to lift a stone. The stronger your Blood Qi, the heavier the stone you can lift."

"Yes." Su Hao nodded to show that he understood.

Wu Yuntian finally smiled. It was a smile Su Hao rarely saw. Then he said, "Now that you understand this much, we can get to the main point."

After a pause, Wu Yuntian said, "What we call Blood Qi training methods are essentially ways to increase the body's energy. The more energy, the more Blood Qi accumulated within the body, the stronger a Martial Artist becomes. When the body's energy reaches a certain level, one can even shatter a mountain with a single punch."

Isn't that a nuclear bomb? Su Hao stared at his father in shock. "Father, have you ever seen a Martial Artist like that?"

To his surprise, Wu Yuntian shook his head. "No. That is merely what the legends say."

Seeing Su Hao's disappointed little face, he explained further, "I only want to tell you that through training, humans have a chance to reach such a level. It is said that the mightiest Ancestor Level Warriors can do it."

Su Hao merely nodded. Wu Yuntian asked again, "Then, Xiangwu, one final question. We carry out a great deal of physical activity every day, so where does the energy for that activity come from?"

Su Hao rushed to answer, "Food!"

"Correct!" Wu Yuntian nodded and explained, "Every day, we eat a great deal of food, and through converting that food, we gain energy. So, Xiangwu, eat more from now on."

Wu Yuntian was rarely so gentle. "Xiangwu, you are the smartest child I have ever seen. Even at the age of six, when one begins learning martial arts, not everyone understands these principles from the start. I hope that one day, you truly can become a powerful Martial Artist of the Human Race! I hope that you... can break the shackles of a Martial Artist's Bloodline."

Su Hao asked in confusion, "What are the shackles of a Martial Artist's Bloodline?"

Wu Yuntian shook his head. "You will understand later. Let us return to the subject of gaining energy from food."

"Do you know Little Fatty at the sentry post?"

"I do."

"Good. Beyond providing the amount we need for normal activities, the food we eat leaves behind a great deal of surplus. That surplus is ultimately converted into energy. There are two directions for this conversion. One is the Blood Qi I just mentioned. This kind of energy is highly active and can directly increase strength. The other is fat, which is stored away and makes a person look fatter.

But the human body's default conversion direction is to turn it into stored fat, because fat can be stored longer. The so-called Blood Qi training methods are essentially about intercepting the portion of energy that would be converted into fat, making it transform into Blood Qi instead and storing it within the body."

"And Little Fatty is an example of failed conversion. In other words, if you start learning martial arts too early but fail to convert it properly, you will..."

"Get fat!"

Su Hao's eyebrow twitched again. There was even such a risk? At the thought that he might become a chubby little boy in the future, lingering fear rose in him.

At that moment, Wu Yuntian took a book from his robes and handed it over. "Go back and memorize this book first. Once you have memorized it, I will take you through it so you can understand it."

Su Hao took it and looked. "Nine Palaces Blood-Intercepting Manual."

"The name's not bad."