It's important to clarify some things at the beginning.
The original Lee from the anime and manga was a true prodigy in the realm of Taijutsu, a one-in-a-million talent, on par with Might Guy and his father. To learn to open the Five Gates out of the Eight in just a year and a half is a sign of being incredibly advanced in the art of body manipulation. However, it's also worth noting that without his teacher, Lee might not have achieved such success. Still, the fact remains that he had an innate talent for martial arts.
Lee is a Taijutsu genius who only needs the right mentor and motivation.
However, the revived Madara, Obito, Nagato, Kaguya, and the rest of the Otsutsuki family overshadowed all of this. Training isn't necessary when you have genetics and Kekkei Mora. But who said it would be easy?
"The System of Hellish Exercises! With it, I'm going to tear apart the cheaters of the Shinobi world! I want to eventually swallow them up and not even notice! That's another goal of mine in life! To become a master and become the strongest among them! From rags to riches!" Lee's eyes blazed with determination and resolve.
Right now, Lee stood a few meters away from a wooden training dummy with his right leg raised. He repeatedly delivered blows into thin air, occasionally increasing the strength and speed of his movements. However, nothing substantial was happening yet; only a faint breeze was generated from the swift leg sweeps. In general, the Rankyaku he was attempting at the moment was far from impressive, and to be precise, it wasn't working at all.
"It's interesting, why is that?"
In the world of pirates, there wasn't any unusual energy coursing through the body, apart from Haki, a mysterious and unexplained power that allowed for sensing and arming oneself. Therefore, Rokushiki fighting style and Rankyaku were nothing more than compressed, sharp blades of air that needed to be released, nothing more. It may sound simple, but in reality, Lee was stuck, literally standing in place, comparing his training method with the one described in the morning's bronze box.
So...
All that was left was to keep hitting the air again and again, attempt after attempt, with strained tendons and muscles, with a shower of sweat and rising dust, obscuring the view, all in the hope of what?
For a spiritual revelation akin to that of martial arts masters.
However, fortunately for Rock, fate wasn't going to abandon its direct responsibilities. Evidence of this statement could be found in the fact that at that very moment, near the training ground where Lee had been for some time, a man in a green jumpsuit, wearing a vest over it, with thick, wavy hair styled like a glossy pot, was passing by.
Frowning deeply in contemplation, Might Guy, one of the strongest Jonin of the Hidden Leaf Village, closely observed the figure of the young man who appeared to be engaged in something other than training. To the casual observer, it might seem like he was playing with the air, judging by the jerky movements and labored breath of Rock Lee.
Guy couldn't help but shake his head at this, before displaying his usual warm smile as a kind-hearted person would. Besides, Lee was somewhat familiar to him from hearing about his efforts in Taijutsu. Although one could also remember that they had just met not too long ago, albeit unknowingly.
"What are you doing, young man?"
Of course, Lee flinched, lowering his raised leg and being startled by the unexpected, deep, and confident voice that sounded nearby. However, when he opened his round eyes and saw a familiar, equally muscular man walking peacefully along the path, wearing his truly legendary suit with a protector on his waist, Rock let out a quiet chuckle to himself, relaxed, and responded with a friendly nod and the following words:
"Usually, I hit a log, getting used to the loads and pain, but today I decided to simply practice shadow fighting. Why? What's up?" Lee asked in the end.
"Oh, nothing like that, don't think ill of me. It's just that you possess that very Power of Youth, which I live for with burning passion. As a respected follower of the path of Taijutsu, I can't ignore the subtle mistakes you're making, especially while clearly observing how you're giving it your all and striving to improve your skills. But where's the rhythm? You completely lack it! Your lunges are jerky and unsuitable for delivering a good, assertive strike! Just be smoother and follow my lead, okay? Let's go! Let's start!" Guy suddenly and energetically fired up, launching into a lengthy speech before also getting into position, raising his right leg.
"Is this even normal?" Rock wondered, not understanding how Might Guy ended up in front of him in the first place, ready to teach him without any apparent reason. It's worth noting that they weren't close acquaintances, nor was Lee Guy's student, at least not yet.
However, no matter what, Lee was captivated as he watched the man in the green jumpsuit deliver sharp strikes to the air with loud claps, and he couldn't help but marvel at how precisely Guy's movements were executed. Each of Guy's lunges was accompanied by a gust of wind, and most notably, the sound resembled gunfire. Second by second, Guy's right limb seemed to blur before Lee's eyes as his speed exceeded all limits.
Lee's hair, including the short braid behind him, fluttered in the mini-hurricane created by Guy's strikes. The wind caressed and, at the same time, ruthlessly cut his cheeks, like a capricious beast.
Inside, Rock felt the urge to burst into applause, witnessing such an impressive display and truly appreciating it. However, instead of being carried away by emotions, Lee suddenly realized that he didn't have time for this. Guy was performing his "dance" in front of him, but it wasn't for the sake of mere admiration. So, he closed his eyes and blocked out the howling of the wind, immediately entering a meditative state, focusing on his mind and chakra, which peacefully flowed through his channels.
New, vivid scenes of performing the Rankyaku technique played in his memory, not in a flashback but as a conscious awareness.
As for Might Guy, he ceased striking the air and simply smiled broadly. He had accomplished his purpose, so he gave Rock a thumbs-up and disappeared in a puff of smoke.
Meanwhile, Lee felt as if everything had suddenly become clear to him, as if a veil had been lifted. What had previously been obscured by mist now became clear. The inspiration and enlightenment he had sought were finally within his grasp.
At any rate, at this moment, Lee, in a state of deep trance, felt as if the picture of the Rankyaku technique was becoming more tangible in his own hands, literally in his enlightened hands. He had no sense of how much time had passed, how many days had gone by, but when the cold and mysterious moon illuminated the earth, that was when Rock awoke from his meditation. He opened his black eyes and wore the most serious expression on his face.
Following that, his chakra center stirred, and the Tenketsu, particularly in his legs, seemed to pulsate as they felt the surging flow. With a leg swing, Lee manifested a blue energy shell around his right lower limb, then released everything he had accumulated.
A resounding, vibrating sound echoed throughout the training ground. The chakra blade, cloaked in wind and released with a leg swing from Rock, instantly cleaved the wooden mannequin into two parts as smoothly as if it were cutting through butter and art. It displayed immense power and lethal danger but also consumed a significant amount of chakra, roughly about a quarter of his total chakra reserves.
[Chakra: 78%]
"Unlike Ninjutsu and elemental transformations, I released pure, naked chakra here, only taking shape because I kicked the air. Unfortunately, it consumed a lot of energy. This is the first imperfection, showing that I can't achieve it all at once. I'll have to refine it if I don't want to lose consciousness from exhaustion after a few Rankyaku..." Lee contemplated, already devising an approximate plan for his future training sessions.