It had been several days since they left Konoha, and Tsunade, ever attentive to training, used the journey to initiate her young disciple into a new lesson.
"Shikai, if you want to become a true master of medical techniques, it is essential that you understand every detail of the human body," she said.
Shikai, walking by her side with a bag filled with equipment, nodded, ready to listen.
"Each organ, each system has its role. Take, for example, the circulatory system. Without a good understanding of blood flow, treating a severe injury could worsen the situation. Do you know the role of capillaries?" Tsunade asked.
Shikai furrowed his brows, trying to recall the theoretical lessons. "They are the smallest blood vessels, right? They carry oxygen and nutrients to the cells."
Tsunade gave him an approving smile. "Exactly. But if you don't repair them correctly using the *Mystic Palm*, you could cause internal bleeding. An error like that, on the battlefield, could cost your ally their life."
She continued her lesson, showing him diagrams she had sketched on a scroll. Each organ, nerve network, and vein was meticulously annotated, and Tsunade passionately explained the subtleties of medical techniques.
A few hours later, they reached a small, peaceful village by a river. The crystal-clear water, green hills, and surrounding silence made it the perfect place for intensive training.
Tsunade unrolled another scroll and jotted down notes with a swift brush. "Now, let's move on to something more practical. You've already mastered the basic *Mystic Palm*, but the advanced version is far more demanding. It consumes a massive amount of chakra."
She placed a rabbit, which she had skinned herself, on a flat stone. "Observe."
With unmatched fluidity, Tsunade concentrated her chakra in her hands and applied the technique. A green glow appeared, and within seconds, a dying rabbit stirred with vigor. Its organs regenerated before their eyes.
Impressed but focused, Shikai took another test subject and tried to imitate his master. His first attempts were clumsy. Too much chakra at once almost burned the rabbit, causing Tsunade to grimace.
"Steady!" she growled. "This technique is like playing an instrument. You can't force it; you must follow the rhythm."
Frustrated, Shikai took a deep breath and tried again. After several attempts and corrections from Tsunade, he managed to heal the cuts but at a high cost, unable to regenerate organs, the main use of advanced *Mystic Palm*. He fell to his knees, panting, feeling his chakra rivaling that of a nearly exhausted Jonin.
"It's... it's too demanding," he whispered.
Tsunade crossed her arms, her expression serious yet understanding. "That's why you need to increase your endurance. If you can't maintain this technique in a critical moment, it will be of no use to you. Keep training. Besides, when you truly master it, it's not as demanding as you think."
Shikai nodded, knowing that these skills and techniques would be just as useful for conducting experiments with a high success rate.
"Fuck, that annoying Sakura isn't without talent. If she could master it. Speaking of which, I need to make sure Minato's son isn't following that bitch like a dog. Besides, he won't have time; he'll be too busy seeking revenge on Konohagakure."
...
As evening fell, after a long day of effort, Tsunade decided to relax in her own way. She spotted a small tavern in the village and turned to Shikai.
"I'm going to have a drink. You, meditate here and rest. You're still too young for this kind of distraction."
Shikai rolled his eyes. "And you shouldn't waste your money... again."
Tsunade shrugged with a smile. "We'll see. I plan to win today."
"That... I doubt it, Aunt Tsunade."
"I'm sure of it, and you know why?"
Shikai raised an eyebrow.
Tsunade laughed and kissed him on the forehead.
"Because you're my good luck charm, my Shikai."
She walked away, leaving Shikai alone by the river. Exhausted but determined, he sat cross-legged to meditate. As he tried to calm his mind, his gaze was drawn to a scroll slightly protruding from his bag. Intrigued, he took it with care.
"Ah, yeah. I almost forgot about this."
The content was fascinating: detailed instructions on a technique he had never seen before—the ultimate technique. The writing was fluid, almost poetic, and the description spoke of golden and silver chains capable of sealing any attack and rendering an opponent unable to use their chakra.
"The ultimate technique of the Uzumaki clan..." he murmured, recognizing it as the S-rank technique that belonged to Kushina, and even Minato had not learned it.
The details were complex, but the general idea was clear. This technique, while immobilizing the enemy, drained their vital energy and chakra to strengthen the user. Shikai, awe-struck but cautious, realized it was a double-edged technique: powerful but risky for someone who didn't perfectly master their chakra. For the technique could turn against the user, with the chains draining their energy instead of their enemy's.
He spent several hours studying the scroll, trying to memorize the symbols and mudras. When he felt a presence behind him, he hastily closed the scroll and looked up to see Tsunade, an ironic smile on her lips.
"So, what's this scroll about? And I'm still waiting for your explanation about all those seals on your body," she said, crossing her arms.
Shikai smiled slightly but did not look away. "This scroll... Aunt Tsunade, how much debt this time? 3000 ryōs?"
Tsunade sighed and sat down next to him, her expression darker. "I really thought I was going to win this time. It was close."
Shikai narrowed his eyes but said nothing, merely nodding. The time was not yet right. He intended to let her sink deeper into her vices.