It was eight days later that both Min-Su and Jin managed to use 'coating' without much difference in their timing. A few hours being the determining factor. Yet both remained in the yard and kept training that principle. Just managing to coat once didn't mean that they truly knew how to do it. Now that they were familiar to success, they would have to repeat it until they knew nothing else.

As he watched the white incorporeal shine of the energy that coated his arm and the one coating Min-Su's legs, Jin couldn't help but marvel at it. It felt very different from the usual spiritual energy he came in contact while cultivating. It was something else while remaining the same. This particular energy seemed to be his from the start. He didn't have to 'will' it to do anything. He could just move it. It was a peculiar feeling.

Beyond that, he could also see it. He was unable to see the wild spiritual energy dots but could see the energy coating himself and the one coating Min-Su. It was unexpected and a beautiful surprise.

As he thought so, he asked Min-Su if he felt the same and the teenager answered him positively: "Yeah. After all, this is your energy and not something else's"

Outside of the fact that Min-Su agreed, Jin found the someone else's curious. It was the first time he thought about it but where did the spiritual energy even come from? After all, there wasn't any in his previous world. Where did it come from? He tried asking Min-Su but the teenager didn't seem to know: "Where it comes from? No idea. But does it matter?"

Jin had to admit he had a point. Why argue with the good things? He placed the question at the back of his head though. He had plans to ask Hae-Hyuk later on... It wasn't like the answer would change his life but as he learnt more and more about this strange energy, he became more and more curious. If he had to use it, wouldn't it make sense to truly understand it?

As such, it was at diner that he asked Hae-Hyuk about it and that man, as usual, had an answer to give: "It is the energy of life granted by the world and the heavens themselves" But that didn't make much sense to Jin. The world? The heavens? What did they refer to? They couldn't be the sky and earth. Or was it some surnames to special entities? Yet when he asked, he was told: "The heavens are the heavens and the world is the world, don't think too much about these and focus on learning the four principles"

Either Hae-Hyuk didn't want to tell him or he didn't know himself. Regardless, he wouldn't get an answer now. Since he couldn't, it was better to give up and move on to what he could do and mattered. So, he kept asking about the principles, mostly about practical ways to use them.

A case of content theft: this narrative is not rightfully on Amazon; if you spot it, report the violation.

After mastering 'coating' at a satisfactory level according to Hae-Hyuk, they had to incorporate it in battle. From that moment on, Min-Su and Jin had dozens of spars every day. Both made tremendous progress. Min-Su was a very talented youth, capable of being qualified as a genius of geniuses. Jin was a master in his past life with experience like no other teenager could rival. Their rivalry brought incredible results, overcoming even the highest expectations Hae-Hyuk had. In a mere four days, they became capable of fighting an opponent while keeping up their 'coating' and not just that, they could truly 'use' it correctly.

Hae-Hyuk was very satisfied to the point that he told them to move onto another principle. That's when their paths changed. Min-Su argued that they should move to External Manipulation while Jin insisted to work on Fine tuning. Both couldn't agree and they weren't able to convince the other. In the end, they asked Hae-Hyuk. He told them that they could pick whichever they wanted to.

The only rules there were when learning the four principles were to start with 'coating' and finish with 'Domain'. As for External Manipulation and fine tuning, the order didn't matter much as both techniques were independent of each other. They both required 'coating' but nothing else. Domain on the other hand required the mastery of the previous three.

It took Jin far longer to grasp fine tuning. Min-Su had long finished learning External Manipulation at the time when Jin only managed his first few successful attempts at Fine Tuning. And it was only because he had a deep grasp on human anatomy thanks to his martial arts background. He was able to skip a lot of learning of the human body and could start working on it physically early on.

Min-Su, on the other hand, didn't have such background. Hae-Hyuk dumped him dozens of books to read, learn and comprehend before he was allowed to attempt it. Of course, the teenager had grumbled and called for favoritism. Jin didn't have to read the books, why did he? But as he began to read and learn, he stopped his whining. This kind of knowledge was truly necessary and he lacked it. He was no fool and understood the facts. At this point, he couldn't help but reevaluate his junior disciple.

Jin persisted in training. He was joined by Min-Su after some days had gone by. And it was surprisingly Min-Su who finished training 'Fine Tuning' first and moved on to the last principle 'Domain'. It wasn't that Jin was slower or less talented. In fact, he had long gone beyond what Hae-Hyuk required in mastery level. But he refused to stop training this particular principle.

Hae-Hyuk himself didn't mind. Quite the opposite. Both disciples would have to train all principles further than he had asked after all. Especially fine tuning for certain reasons... So, seeing that one of his apprentices was so hell-bent on learning more about this principle was good. Which teacher would be against a student trying to learn more than asked to? None.

Min-Su wasn't gloating about him moving on faster either. He had understood that Jin tried to understood the principle further. But he didn't plan to for now. He considered it a must to first grasp all four principles before attempting to reinforce his mastery in each. One could learn from one principle to better himself in the other. That's what he believed.

Neither approach was wrong.