In the sealed space, once Naruto figured out how to measure Chakra, he immediately pulled out a batch of Redstone Lamps from the system.
To avoid messing up the aesthetics around the villa later, he specifically carried the items over to the open area near Kurama's cage.
He hadn't started renovating around Kurama's space yet, so it was the perfect spot to build an experimental field.
Holding the Redstone Lamps in his right hand, Naruto began laying them out one by one in a square formation on the ground.
100 Redstone Lamps dimly glowed red within the sealed space, giving off an eerie but beautiful glow.
When Kurama saw Naruto's actions, he was filled with question marks.
He didn't know what the point of Naruto doing this was.
'He was clearly practicing the Shadow Clone Technique one moment, but how come he was playing with cubes in the sealed space the next?'
'Could it be...'
'Is this brat slacking off?'
Kurama remembered how Naruto had fallen asleep while refining Chakra before and immediately started to feel annoyed.
"Brat, what are you doing?"
Kurama's tone was a little harsh.
If Naruto didn't give him a proper explanation, Kurama was seriously considering teaching him a lesson.
'I have even put aside my dignity to teach him, but this brat doesn't even appreciate it?'
"Big fox, I'm doing something that could change the Shinobi World."
"Remember what I said earlier about measuring Chakra?"
Naruto spoke while inspecting the Redstone Lamps.
"What nonsense are you spouting now?"
Kurama didn't understand and just thought that Naruto was crazy again.
'What measuring Chakra...'
'Just look at Senju Hashirama and Uchiha Madara… even Six Paths old man didn't care about such trivial matters.'
'Do you think you become stronger if you create something that can measure Chakra?'
'Ridiculous!'
"Stop messing around and get back to training!"
Kurama has gradually lost his patience.
'This kid hadn't even finished the tree-punching exercises for the year, not to mention the Shadow Clone Technique.'
'But now he wanted to hide in here and play now?'
'This brat clearly hadn't taken my words to heart.'
"Watch closely, Big Fox!"
Naruto placed his hand on one of the Redstone Lamps, then closed his eyes and prepared to input Chakra.
A moment later, one lamp lit up.
Then two… then three…
The number slowly climbed, until it stopped at twenty.
Kurama became even more confused when he saw the glowing red lamps on the ground.
Meanwhile, Naruto jumped up with joy.
He had just poured in about the same amount of Chakra it took to use a single Shadow Clone Technique.
And that was without using any of Kurama's red Chakra.
"Twenty, huh?"
"So this is probably the amount of Chakra a normal Shinobi needs to perform one Shadow Clone?"
'Now, here comes the question...'
'How much Chakra do I have?'
'If one Shadow Clone = 20 lamps...'
"Hiss…"
Naruto instantly sucked in a sharp breath.
'It seems... I have never calculated how many times I can use shadow clones before...'
'Just today alone, I had used this technique more than 5,000 times during training.'
'And judging from my current Chakra Reserves, I hadn't even used up half of it.'
'In fact, my Chakra was recovering faster than I could burn it.'
For the first time, Naruto had a clear, visual sense of how much Chakra he actually possessed.
'Damn… no wonder people called the original Naruto a Chakra monster!'
He went on to pull out some other items, like the Magic Lamp and the Magic Chandelier, and then compared them to the Redstone Lamps to get a rough energy conversion rate.
Finally, we figured out the energy ratio between them.
20 Redstone Lamps = 1 Shadow Clone
100 Redstone Lamps = 1 Magic Lamp
1000 Magic Lamps = 1 Magic Chandelier
With that formula, Naruto roughly calculated that his current Chakra Reserves were somewhere between 80 to 100 Magic Chandeliers.
That is to say, without relying on Kurama's Chakra, he could cast up to 500,000 Shadow Clones.
And that was without factoring in his natural Chakra regeneration.
Even Naruto himself felt this amount of Chakra was too outrageous.
Back when he was just watching Naruto in his previous life, he'd never had a concrete grasp on what Uzumaki-level Chakra really meant.
All he knew was that people always said the Uzumaki Clan had ridiculous Chakra Reserves.
And as the main character, Naruto pretty much never ran into a 'Chakra not enough' problem.
Only now did he finally understand how powerful the Uzumaki bloodline really was.
"Alright, from now on, I'll be using Magic Chandeliers as the measurement of my Chakra Unit!"
"Hmm... I'll call the unit 'Ma'." (T/N: I'll just use the RAW as the name. Because Ma means Magic, and it's strange to call a Chakra Unit.)
Looking at the three arrays laid out in front of him, Naruto felt strangely proud.
He knew that he had created history in the Shinobi World.
Having observed all this for a while, Kurama finally started to get a rough idea of what Naruto was trying to do.
But he was very disdainful of Naruto's '100 Ma' of Chakra.
Just now, Kurama had tried to estimate his own Chakra, but found that his brain was about to burn out and he still couldn't figure it out.
In short, the Chakra he accidentally leaked was already way more than Naruto's total...
"Brat, I don't see the point of any of this."
"For example, you can't even calculate my Chakra."
Naruto: "…"
'Can you hear yourself right now?'
'Do you even know how much Chakra you have?'
'Who in their right mind has the free time to sit around calculating your Chakra???'
'Besides, this whole thing was meant to assist in practicing Ninjutsu.'
'In the future, it will be even possible to detect how much Chakra my enemies have.'
Though honestly, Naruto felt that last part might not be that useful.
Because from here on out, most enemies he faces probably won't have more Chakra than he does anyway...
"Big Fox, just watch!"
"I'll prove to you this thing's actually useful!"
With those words, Naruto exited the sealed space and his consciousness returned to the real world.
He sat up from the ground, picked up a stick, and began scribbling on the dirt.
Hiruzen, who had watched everything through his crystal ball, was getting a headache.
When he saw Naruto refine Chakra in less than a day, he was shocked… but also thrilled.
The time it took to refine Chakra alone was proof that Naruto is a genius.
This also means that the future of Konoha Village just got a whole lot brighter.
Moreover, ever since he gave Naruto the Shadow Clone Technique, he had stopped endlessly practicing Ttaijutsu, and instead dove deep into mastering the Shadow Clone Technique.
That's good news.
But then…
Something that gave Sandaime another headache started happening...
'He clearly had talent...'
'So how come he hasn't mastered the Shadow Clone Technique after using it thousands of times?'
'A normal Shinobi could get it down in a few hundred tries!'
Then, Hiruzen saw Naruto gave up practicing the Shadow Clone Technique and started scribbling something on the ground.
Stuff he couldn't even understand.
'What the hell was going on in his head?!'
'Don't tell me… He is actually trying to create a new Ninjutsu???'
'But why was there also a lunch menu written in one of the corners??'
Hiruzen could feel his blood pressure spiking.
Naruto was naturally thinking about what to eat for lunch while he was working.
But for now, his priority was still mastering the Shadow Clone Technique.
"Big Fox, what do you think?"
When Naruto was calculating, he asked Kurama to monitor how much of the red Chakra was accidentally leaking into his techniques.
"Make the hand seal, I'll tell you."
Naruto nodded, took a deep breath, recalled what one Chakra Unit of Redstone felt like, and began to form the hand seal.
As he formed the hand seal, red and blue Chakra appeared in Naruto's body again.
"Fifteen units of Redstone Chakra."
"Feel it for yourself."
Naruto did not use the Ninjutsu, but just let the Chakra flow in his body. He was also trying to sense the extra Kurama's Chakra.
After all, he had to get used to the feeling of Kurama's Chakra leaking in.
Otherwise, he will not be able to master any Ninjutsu he practice quickly in the future.
Kurama's Chakra felt completely different from his own. If his own Chakra was like drinking water, then Kurama's was like swallowing liquid fire, which is very unforgettable and intense.
After remembering this feeling, Naruto opened his eyes and formed hand seal again.
"Shadow Clone Technique!"
Bang, bang, bang…
Two figures that looked exactly like Naruto suddenly appeared at his side.
"Success!!"
Seeing that he had performed the technique successfully, Naruto grabbed his clones and started spinning in circles with them like a kid at recess.
"Idiot."
At that moment, a cold, unfamiliar voice suddenly rang out in Naruto's ears.