Renjiro looked at Feng Zheng and said, "I have already taught you everything about the Senju Taijutsu Style. How much you master is up to you."
Feng Zheng bowed slightly and said, "Thank you, teacher."
Seeing his humility, Renjiro's expression softened. He said, "You once mentioned that even the Sannin do not possess a Bloodline Limit. Lady Tsunade, one of the Sannin, utilizes an advanced form of Senju Taijutsu Style."
"She has refined this style to complement her perfect Chakra control, making it even more lethal. Your talent in this area is also very high, so you must work hard to learn it."
Feng Zheng nodded and said, "Yes, teacher. I will continue to improve."
Renjiro continued, "Speaking of which, it's now time to refocus on Ninjutsu and Kenjutsu. We'll practice all your Ninjutsu first, and then we'll start enhancing their power."
Upon hearing this, Feng Zheng immediately became excited. Renjiro noticed and narrowed his eyes. He asked, "Have you already tested it?"
Feng Zheng chuckled nervously, then confirmed it. Renjiro sighed and said, "I hope you didn't break anything."
Feng Zheng obediently shook his head and said, "Teacher, don't worry, I shot all my attacks directly into the sky."
Renjiro asked, "Alright. So, what were your observations?"
Feng Zheng replied, "Ninjutsu enhancement takes a very long time. So, unless I can significantly shorten the time, it's unusable in combat."
Renjiro nodded.
Feng Zheng continued, "Beyond that, none of my other Ninjutsu can be enhanced. Rock Shield Technique, in particular, showed no improvement whatsoever. Great Breakthrough Technique and Wind Dragon Technique had the best enhancement effects."
Renjiro said, "Yes, that's how enhancement works. While you can inject a large amount of Chakra into any Ninjutsu, not all Ninjutsu can be enhanced. The amount of Chakra you can inject also depends on your Chakra reserves, Chakra control ability, mastery of elemental release, mastery of that specific Ninjutsu, and the Ninjutsu itself."
"Although Konoha lacks Wind Release Ninjutsu, you are fortunate to have Wind Release talent. This is because almost all Rank C Wind Release Ninjutsu can be enhanced. As for Rock Shield Technique, its defensive capability is inherently low. So, don't worry about it."
"Over the next few months, I will teach the three of you how to quickly enhance your Ninjutsu in combat. Since your Chakra reserves are the highest, you will need to put in the most effort in this area."
"Before we begin, do you have any other questions?"
Feng Zheng nodded and said, "Yes, teacher. I have a few questions. The first is related to Rock Shield Technique."
"I can now cast Ninjutsu without any Hand Seals, but I still need to slam my hands on the ground. Do you know of any way to cast Ninjutsu by stomping your foot on the ground?"
Renjiro raised his left eyebrow and asked, "Why do you want to do that?"
Feng Zheng said, "It would greatly improve the efficiency of casting Ninjutsu. If I'm holding a sword, I'd have to temporarily put it down to place my hands on the ground, which doesn't seem like a good idea."
"If I could cast Ninjutsu with my foot, I could use it while fighting with my sword. And if an enemy launched a large-scale attack on me, I could also retreat while stomping my foot on the ground to form multiple rock shields."
Renjiro was surprised by Feng Zheng's tactical thinking. He replied, "That's a good idea. I never thought Rock Shield Technique could be used like that. I presume your intention is to eventually apply this method to all Earth Release Ninjutsu, right?"
Feng Zheng nodded and said, "Indeed, that would be very convenient."
Renjiro continued, "Unfortunately, that's impossible. Or rather, at least, it's not easy. The Hand Seals for that Ninjutsu gather Earth Release Chakra in your palms. While you can cast this Ninjutsu without any Hand Seals, it merely replicates the way Chakra is shaped when performing the Hand Seals."
"What you're suggesting is no different from creating a completely different Ninjutsu."
Feng Zheng quickly said, "In that case, teacher, can't we create such a new Earth Release Ninjutsu?"
Renjiro shook his head and said, "That's too difficult. While minor Ninjutsu can always be created, the method you're describing would completely revolutionize Earth Release Ninjutsu, and at least I can't do it."
"Furthermore, while your idea is very creative, it's unlikely you're the only one to have thought of it. Considering that, to my knowledge, no such Ninjutsu exists, it's safe to say that no one has been able to create it."
Feng Zheng felt a little depressed upon hearing this.
"Alas, an idea I had for endlessly bothering enemies is gone just like that."
Seeing his dejected look, Renjiro smiled. Feng Zheng looked back at Renjiro and said, "Since my Rock Shield Technique can't be improved any further, can I train in Earth Release: Earth Flow Wall?"
Renjiro shook his head again and replied, "No, that's a Rank B Ninjutsu. While your Chakra reserves are good, you shouldn't rely on Ninjutsu above Rank B until you've been promoted to Chunin."
This answer was exactly what Feng Zheng had expected. So he asked his last question.
"Teacher, when training in enhanced Ninjutsu, my Chakra runs out very quickly. Do you have any other ways to quickly increase my Chakra reserves? After all, the training of injecting Chakra into the body has almost no benefit in this regard anymore."
A look of disbelief appeared on Renjiro's face that Feng Zheng would ask such a question. He said, "Kid, do you think Chakra is sold at the grocery store? Your Chakra reserves are already four times that of your teammates."
"Be content with that, don't be greedy. Also, don't bother looking for more ways to increase Chakra reserves. Almost all methods, besides diligent training and natural growth, have some form of flaw that will severely limit you."
"As for during combat, you can always eat soldier pills to boost your stamina. So don't bother anymore."
Feng Zheng was somewhat shocked by Renjiro's dismissive attitude. He thought to himself, "Really, is there no other way? Alas, it seems I was expecting too much. After all, the current improvement is already very high."
"Sigh, never mind. I'll save this question for later. If I really need Chakra, I can try to steal a Tailed Beast."
Thinking of Tailed Beasts, Feng Zheng sighed in his heart.
"How great would it be if I could throw some Poké Balls to catch them."
Renjiro asked, "Any other questions?"
Feng Zheng shook his head and said, "No, teacher, let's begin."