Early the next morning, as soon as Tsunade left the house, Nawaki impatiently hurried over to Minato's side. He looked at Minato with an expectant and pitiful expression that clearly begged for the promised training to begin. Minato could not help but offer a gentle, polite smile as he led Nawaki into the courtyard. Once they were positioned, Minato pressed his hands together in a simple seal. Suddenly, a wooden stake as thick as a washbasin sprouted from the earth directly in front of him. Minato then extended his right hand toward Nawaki and told him to watch closely.
As he spoke, a chaotic surge of Chakra gathered in his palm. It began spinning at an incredible speed until it condensed into a high-density Chakra sphere. The rotating energy kicked up a wild current of air that ruffled both of their hair. Nawaki's eyes sparkled with awe at the sight of such strong Chakra and he eagerly asked for the name of the move. Minato replied that it was called the Rasengan. Without further delay, he turned and slammed the sphere into the wooden stake. The moment the Rasengan touched the wood, it blasted a large, spherical hole clean through the center.
Nawaki stared blankly at the hole in the stake, lost in thought for a moment before becoming uncontrollably excited. He demanded that they start cultivating the technique right away. Minato gently raised his hand to signal that Nawaki should calm down first. He explained that before they could proceed, he needed to test Nawaki's current level of Chakra control. Nawaki was eager to try and asked what he needed to do. Minato clapped his hands together again, causing the broken wooden stake to shoot up over $10$ meters. Its top sprouted countless branches, transforming it into a tall, straight tree.
Minato then stepped onto the tree trunk and walked up to the very top, step by step, as if he were walking on level ground. He explained that one must distribute Chakra evenly on the soles of the feet to balance with their own body weight to walk freely on walls. Nawaki took a few steps back and charged excitedly toward the tree. He managed three successful steps before his foot slipped. His body tipped backward, and the back of his head went crashing toward the ground. Minato had already anticipated the mistake and instantly appeared beneath Nawaki to catch him steadily.
Nawaki looked frustrated and embarrassed, especially since Minato was holding him in a princess carry. Minato smiled and comforted him, suggesting a method to help him master Tree Climbing quickly. Minato pressed his hand against the trunk, and a branch as thick as a bowl's rim extended out at a height of $2.5$ meters. He leaped up and grabbed the branch while resting his feet against the trunk. He explained that holding the branch would allow Nawaki to continuously adjust his Chakra output more effectively than blindly charging up. Nawaki laughed and joked that Minato looked like a koala.
Minato snapped the branch off with a sharp crack, looking regretful. He suggested that since Nawaki didn't like the method, they could try something else. Nawaki panicked instantly and grabbed onto Minato's leg as he jumped down, insisting he loved that way of cultivating. Minato smiled, patted the trunk, and grew another branch. After Nawaki leaped up and hugged it, Minato's expression shifted. He formed Hand Seals and whispered "Earth Release: Earth Spear." Sharp spikes of earth suddenly grew all around the tree trunk. Nawaki's face turned pale as he saw the danger.
Minato told him seriously that many powerful Ninjas breakthrough their limits during life-and-death moments. He told Nawaki that if he wanted to become the Hokage, he had to push himself to find his true potential. With that, Minato said he was going grocery shopping and vanished from the spot using a Body Flicker. Nawaki immediately panicked and began shouting for Minato to come back, apologizing for his earlier jokes. Minato's smile was very bright as he heard the cries. Internally, he knew the earth spears were just clay-like props that would crumble upon touch within $2$ minutes.
In the courtyard, Nawaki hugged the branch tremblingly. He looked down at the forest of sharp spikes and swallowed hard. His arms felt increasingly sore and his palms were drenched in sweat. He cried out piteously to a nearby Wood Clone, begging for help. The Clone glanced at him and claimed it was just an ordinary Clone. When Nawaki tried to act friendly, the Clone huffed and turned away, while several other Clones burst into laughter. Nawaki screamed in frustration, but then a gust of wind blew, and the earth spears collapsed silently like melting ice cream.
Nawaki realized he had been played, and his face flushed bright red with anger. He cursed Minato for being a black-bellied guy with a naturally evil heart. Two hours later, Minato returned from shopping. As he entered the house, Nawaki dropped from above and tried to punch him. However, the Minato he hit exploded into a wooden stake. Nawaki was surprised by the Substitution, and suddenly felt a cold ice pop held against his neck. Minato appeared behind him with a hint of amusement, declaring the match a knockout. Nawaki took the treat, acting triumphant because he had finally learned Tree Climbing.
Minato carried the groceries inside and pointed to the small pond in the courtyard. He explained that the next step was Water Surface Walking. This required constantly adjusting Chakra output according to the water's flow. Nawaki was getting impatient and asked if he could just learn the Rasengan directly. Minato shook his head, explaining that Chakra cultivation involved Shape Transformation and Nature Transformation. He noted that the Rasengan was the pinnacle of Shape Transformation. Theoretically, mastering it meant one could learn almost any Ninjutsu. Nawaki was stunned, realizing the immense value of the technique.
Nawaki asked how long it had taken Minato to learn it. Minato replied that it took about $3$ months of pure cultivation. Nawaki's tone became complex as he processed this. He believed that if Minato could master such a difficult technique in $3$ months, he could master anything in that timeframe. Minato did not correct Nawaki's internal thoughts. In his own mind, Minato knew the truth was much more extreme. He didn't need months; he was the type of genius who could usually learn most Ninjutsu just by looking at them a single time.
----------------
You can read advanced chapters here: patreon.com/GregariousLion