Mud to Stone

On the first floor, in the stairwell, some miscellaneous items were piled here, and few people usually came by. It was quite suitable for placing the tunnel entrance here.

Of course, he would not blatantly pry up the floorboards. Instead, he had Hei Bei dig a small hole leading underground, then let him get to work beneath it.

"How is it? How efficient are you?" Kamiya Keiyun asked from above.

"My paws are more than ten times stronger than before! In no time at all, I can do as much as I used to in an entire night!" Hei Bei said excitedly. "But where do we put all the dirt I dig out?"

"This..." Kamiya Keiyun thought about it. Right, that did seem to be a problem!

They needed to dig a hundred meters down, then eventually extend it beyond the village. Even if the tunnel did not need to be too wide, the amount of excavated soil would still be enormous.

Kamiya Keiyun grabbed a handful of dirt and thought for a moment. "Pile it in the backyard for now. Tonight is only to test your digging speed! As for the dirt, I'll think of something."

"Okay! Don't forget that you promised to feed me!"

"Of course I won't!" Kamiya Keiyun smiled, but as he kept smiling, he felt like crying.

Right, rats needed food too!

Not to mention that after today, Hei Bei's two older brothers and three younger sisters would be coming as well.

One rat did not eat as much as a cat, but there would be six of them now.

And after becoming Ninja Beasts, their appetites had grown even larger!

"Still, Roof Rats are omnivores. Maybe I should find a grain merchant to work with." Kamiya Keiyun thought about it, only to realize that he did not even know which family in the village dealt in grain.

In fact, because he had spent so much time staying at home before, he did not know much about Konoha. He also knew very little about its various political structures.

When he got up before dawn, Kamiya Keiyun was stunned to see a pitch-black rat lying peacefully in Ruri's arms. The two little creatures were sleeping soundly.

"Uh..." Kamiya Keiyun was shocked. This worked too? Weren't cats and rats natural enemies?

But then he thought about it. Even in his previous life, pet cats generally would not attack pet rats raised by their owners. Besides, Ruri was now a cat that could speak and communicate with people.

Kamiya Keiyun got dressed, then knocked on Hei Bei's head.

"What?" Hei Bei said impatiently. "I'm tired to death!"

"Fine." Kamiya Keiyun nodded. After all, Hei Bei had worked all night, so he would not disturb him.

He glanced toward the backyard. Sure enough, quite a lot of dirt had already been piled there—a heap over a meter high.

When he went downstairs, Kamiya Koromo had already prepared breakfast. Seeing Kamiya Keiyun come down, she asked warily, "Keiyun, didn't you bring home a cat before? Does it catch rats? I heard a rat digging holes in the house last night!"

"Ah, Mom, don't worry about that." Kamiya Keiyun waved his hand. "I'll handle it. Also, don't worry about the dirt in the backyard. I'll take care of it."

"Oh." Kamiya Koromo nodded. She rarely went to the backyard anyway. It was on the shaded side of the house, and even when hanging clothes out to dry, she used the front yard.

"Right, there's also the noise problem. I need to figure out a solution for that too!"

After breakfast, Kamiya Keiyun took a measuring tape and lay in the stairwell, measuring downward.

He had marked out a circle for Hei Bei, forty centimeters in diameter, and told him to dig straight down.

When he lowered the tape, the hole was actually 2.5 meters deep!

"The formula for a cylinder's volume is V = πrh, so he dug three cubic meters of dirt in one night!" Kamiya Keiyun was somewhat surprised, but then he thought about it. Three cubic meters did not seem like much!

After all, he had only dug 2.5 meters in one night. To reach a hundred meters would take forty days.

By then, it would be far too late!

Even if Hei Bei's whole family joined in, it would only shorten the construction time to six days. And that did not even include the distance they still had to dig underground to get beyond Konoha!

"If only I could awaken an MC System. A mere hundred meters would take less than a minute!" Kamiya Keiyun sighed. He remembered that in MC, when you dug up dirt, it turned into little blocks that could be stuffed into your inventory. There would be no need to deal with it at all.

"Wait?" Kamiya Keiyun froze. MC System, little blocks?

Kamiya Keiyun began to let his thoughts run wild. He did not have an inventory, but turning dirt into little blocks might not be impossible!

After all, he had previously discovered that Chakra possessed two properties: attraction and repulsion.

If he applied those two properties to dirt and reduced the distance between its molecules, the dirt's volume would naturally shrink drastically. That would solve the problem of where to put all the excavated soil!

Kamiya Keiyun also guessed that the digging itself probably did not take much effort. After all, it was Hei Bei's innate talent. Would the son of a rat not know how to dig holes?

But carrying the dirt to the backyard took a great deal of time. Especially for a rat—he could not use a cart, so he could only move it bit by bit. Perhaps most of his time was spent transporting dirt.

If there were a way to compress the dirt, the project could proceed much faster!

Kamiya Keiyun first went to the backyard and grabbed a large handful of dirt, then headed to school.

Along the way, he began experimenting with Chakra little by little.

He condensed Chakra in his palm, then used it to envelop the dirt resting there.

When the amount of Chakra was low, it displayed an attractive property toward the dirt. When the amount of Chakra was high, it displayed a repulsive property.

But now that the Chakra completely surrounded the dirt, the repulsive force had nowhere to disperse. It could only converge entirely upon the dirt in his palm.

Then, the molecules of each substance making up the dirt were compressed by the omnipresent Chakra and naturally began to gather toward the center.

After experimenting bit by bit and working at it little by little, he spent the entire journey researching it, then continued trying for two classes in the classroom. The fist-sized clump of dirt in Kamiya Keiyun's hand eventually became an egg-sized, pitch-black substance resembling a stone.

"It actually worked! But its volume only shrank by about one-third. That's still not enough!" Kamiya Keiyun tossed the stone-like object in his hand. Stone and dirt did not differ much in density. If it only shrank this much, he would still need somewhere to pile it.

At most, he would turn a pile of dirt into a pile of stones. But square stones would be far too easy to notice. He might as well pile up dirt instead!

"Still, this level of precise Chakra control feels inferior to Hand Seals!" Kamiya Keiyun thought for a moment, then began trying to use Hand Seals to manipulate Chakra.

He was already extremely proficient with the twelve seals. He also knew that they corresponded to various changes in Chakra. Combined with the flow of Chakra he had just observed, working backward from the result to determine the seals was not difficult.

Sure enough, Kamiya Keiyun discovered that using Hand Seals abruptly increased the precision of his Chakra control by a great deal.

If Kamiya Keiyun's control over Chakra had been 1 when he had first extracted Chakra, then after cultivating the Bright Virtue Method and beginning to shape a human form, his control over Chakra had become 10. With mental focus and Hand Seals combined, his control over Chakra became 30!

The instant he completed the seals, a slightly stronger stream of Chakra surged from his palm and entered the already compressed stone. Then, the stone that had already been compressed to the size of an egg was compressed once again, becoming the size of a pigeon's egg!

"!!" Kamiya Keiyun stared in astonishment at the dark brown stone in his hand, which looked like a pigeon egg. Then he thought of the clump of dirt he had taken when leaving home. Its volume had directly shrunk by three-quarters!

"That's it!" Kamiya Keiyun was somewhat excited. What did the success of this technique mean? It meant that one cubic meter of dirt could be condensed into 0.25 cubic meters of stone!

And Kamiya Keiyun felt that this technique had not reached its limit yet. He had only tried it once or twice. If he improved it further, he might be able to condense it down to 0.1 cubic meters, or even 0.05 cubic meters!

For now, it was merely Mud to Stone. But in the future, it would be turning earth into steel and stone into gold!

"But why do I feel like I have some kind of special affinity with dirt?" Kamiya Keiyun felt the dirt in his hand. He had sensed it when trying to compress it just now. This dirt felt like a part of his own body, exceptionally familiar. He had barely needed to exert any effort!

But he had not felt this way when playing with water before.

"Is it because I chose to strengthen my leg muscles? Or because I come from the land of flowers, and farming is in my blood?" Kamiya Keiyun thought about it, then recalled the electricity around Hatake Sakumo when he attacked, as well as Shimura Ken's nickname, Wind Ghost. So that was it—this was an attribute! An affinity for a particular element?

So Hatake Sakumo's primary attribute was lightning, Shimura Ken's was wind, and his own primary attribute was dirt?