The original Mud to Stone Technique could only compress mud into the same shape it had been wrapped in, merely reducing its volume.
Kamiya Keiyun wanted to alter it so that the earth would compress outward from the center, ultimately turning a cylindrical mass of mud into a circular stone pipe.
That would not only solve the problem of stacking stone bricks, but the pipes themselves would also bear weight and keep out groundwater, insects, and the like.
He had thought it would be difficult, but after only two or three attempts, he discovered that he had succeeded!
Changing the shape of the compressed earth was practically effortless. All he had to do was picture it in his mind, and it worked immediately!
"The Mud to Stone Technique has a full twelve hand seals, far more than the Three Body Technique. But in terms of difficulty, there doesn't seem to be much difference?" Kamiya Keiyun had thought he had created a fairly difficult technique, yet judging by his own experience, it did not seem hard at all.
Unfortunately, this technique consumed quite a bit of Chakra. Even with his high affinity for earth, it still required that much.
He estimated that his Chakra could only support four uses of the technique, each one reaching five meters deep. In other words, he could dig a twenty-meter-deep passage in just a few minutes!
His Chakra took eight hours to recover. Altogether, he could use it eight times a day, or perhaps twelve.
Then, Kamiya Keiyun passed the advanced variation of the technique to Hei Bei and watched him perform hand seals with his claws.
"Did you learn it?" Kamiya Keiyun asked.
"I think I get it, but I can't find that feeling you described—the feeling of becoming one with the earth!" Hei Bei replied. "And it consumes a lot of Chakra. All the Chakra in my body can only use it once, and I can only dig one meter deep! If I use too much Chakra, I get dizzy and feel like my body's been hollowed out."
"That can happen?" Kamiya Keiyun was somewhat curious. He had never completely exhausted the Chakra in his body, mainly because he had no real means of consuming it. It was not like he could keep using the Transformation Technique all day!
As for Hei Bei being unable to become one with the earth, that was probably because he lacked Earth Style.
"Chakra is the fusion of physical energy and spiritual energy. If Chakra is consumed, that means physical and spiritual energy are consumed too. Maybe that really can happen." Kamiya Keiyun thought for a moment, then said, "Then control your Chakra output. Don't dig so deep. Sixty centimeters at a time is enough. Once your brothers and sisters arrive, all six of you can work together and dig 3.6 meters at once! Then recover your Chakra. Advancing thirty meters in one night shouldn't be a problem."
"How can Chakra recover that quickly? The Chakra I used up last night took half a day of sleep to recover!" Hei Bei said.
"So without using ninjutsu, you can dig 2.5 meters in one night. But if you use ninjutsu, you can only dig 0.6 meters in one night?" Kamiya Keiyun asked.
Hei Bei fell silent. Though he did not want to admit it, that did seem to be the case.
"Did I... fail to help you?" Hei Bei asked softly.
"No, that isn't your fault!" Kamiya Keiyun shook his head. "After all, you're only a mouse. Your Chakra reserves definitely aren't as large as mine, and you don't have Earth Style Chakra either, so manipulating earth must consume even more."
So rather than having Hei Bei dig the tunnel, it was better for Kamiya Keiyun to do it himself. His Chakra recovered quickly enough that he could use the technique twice a night and dig forty meters. In three days, he could reach a depth of one hundred meters!
Konoha was not very large, only about nine hundred meters in diameter according to a calculation by Bilibili uploader Zuishangchuan Xiashan. Kamiya Keiyun's home was only three hundred meters from the wall. To be safe, he could dig four hundred meters, which would only take ten days.
Adding the time needed to dig upward, it would take fourteen days in total to get out!
Subtracting those fourteen days, there were still fifteen days left until October 5th!
That was enough!
"Then it's settled!" Kamiya Keiyun said. "No time to lose. We start tonight!"
That night, after Kamiya Koromo and Kamiya Hiromi had gone to sleep, he first sent Hei Bei out to carry a Wooden Stakes infused with Kamiya Keiyun's Chakra into the pit. Then Kamiya Keiyun used the Substitution Technique!
Kamiya Keiyun instantly passed through the floor and appeared inside the deep pit!
"It's a little dark." Kamiya Keiyun looked around. The space was incredibly cramped, only large enough for one person. He could turn around, but sitting down would be uncomfortable.
Still, that was just right. Since he could not see the surroundings, he did not feel claustrophobic. Kamiya Keiyun directly formed hand seals, then pressed both hands against the ground and poured Chakra into the soil.
"Earth Release: Mud to Stone Technique!"
Boom!
Under the effect of his Chakra, the earth beneath Kamiya Keiyun instantly became a smooth pipe five meters long and forty centimeters in inner diameter. The ground beneath his feet vanished, and he fell straight down.
But it was not a big problem. It was only five meters.
Kamiya Keiyun continued forming hand seals.
Boom!
"Hm? This time, it seems to have gone a little farther, and the inner wall is wider too?" Kamiya Keiyun's senses were keen, but he did not know the exact dimensions. Fortunately, Hei Bei brought down a measuring tape.
After measuring it, he discovered that the pipe made this time was actually 5.05 meters long, while its inner diameter had reached forty-two centimeters.
His Chakra could extend farther, and its compression of the earth was stronger. That was a sign that his ninjutsu had grown stronger.
If he kept practicing like this, it might not be impossible for one use of the technique to open a ten-meter-long passage in a few days!
"I have the Heaven Rewards Diligence talent. Every time I use ninjutsu, my proficiency keeps increasing. Maybe I won't need fourteen days at all!" Kamiya Keiyun was somewhat excited. But then he reconsidered. Chakra was the product of physical energy and spiritual energy. People moved around every day, so consuming a little did not matter. But if he used too much, it might harm his body.
Since ninjutsu could evolve, there was no need to use Chakra to the point of exhaustion. The original plan had been to use it eight times a day, but now, six times a day would be enough!
He used the Mud to Stone Technique once more, ending tonight's work.
Including what Hei Bei had dug earlier, they had reached a total depth of 17.7 meters!
"Should I keep digging tonight?" Hei Bei asked nervously when he saw Kamiya Keiyun come back up.
"Do you want to?" Kamiya Keiyun asked.
"Of course I don't!" Hei Bei said. After all, nobody liked working, and the feeling of exhausting all his Chakra was far too uncomfortable!
"Then don't." Kamiya Keiyun thought for a moment, then said, "Oh, call Ruri into my room. It's only nine o'clock. Why sleep already? Let's have two hours of lessons before bed!"
"Okay." Hei Bei got up and shot upstairs.
Kamiya Keiyun also rose and went to the training room.
Soon, Ruri and Hei Bei came in, followed by Kamiya Sanyō.
"I... I couldn't sleep either," Kamiya Sanyō said.
In truth, seeing a human, a cat, and a mouse all busy working for her sake, how could Kamiya Sanyō possibly sleep?
"Fine, then sit down first and review the Three Body Technique you learned earlier. I'll teach them literacy over here!" Kamiya Keiyun took out a roll of blank paper and began reading aloud softly, word by word.
The cat and mouse sat upright beside the small table and listened attentively. Their attitude was far more proper than the students at the ninja academy.
They knew that Kamiya Keiyun's teaching was highly effective, but his time was precious. During the day, he had classes. After school, he had to train his leg techniques and practice ninjutsu. Every day, he only had a little time for lessons.
Kamiya Keiyun's curriculum for them was very traditional. First came the Three Character Classic, then Tang poetry and Song lyrics.
Wasn't the Thousand Character Classic supposed to come in between?
That was because Kamiya Keiyun had not memorized it.
There would also be lessons on political thought mixed in.
He did not possess methods for controlling people like the Life-and-Death Talisman or the Three Corpse Brain Pill. Even if he did, he would not trust their effects.
To keep secrets, strengthen their will, and make his subordinates capable of enduring brutal torture, shared beliefs were far more useful than methods.
At the same time, in order to protect the two Ninja Beasts, Kamiya Keiyun would not assign them overly difficult tasks before they became strong enough—for example, having Hei Bei monitor Shimura Ken.
Even if he was a mouse, Kamiya Keiyun was unwilling to take that risk.
After thinking it over, Kamiya Keiyun also decided against having Hei Bei's brothers and sisters join them. First, he might not be able to afford to feed them.
Everyone in the household already knew about Ruri, and Kamiya Koromo could simply make one extra portion of cat food.
Hei Bei ate little, so Kamiya Keiyun could bring back a bit more food each day and make room for him.
But how was he supposed to make room for six mice?
Second, too many mice would be hard to control. With only two of them, the cat and mouse could keep an eye on each other.
If six mice came over, could Ruri keep watch over all of them?
Third, he no longer needed that many workers. He could dig the tunnel himself now.
After teaching them Ode to the Goose, Kamiya Keiyun had the two Ninja Beasts practice writing on their own, then went over to Sanyō.
"Big sister, do you know any way to make money?"
That was right. Now that he had solved the problem of getting out of the village, another problem lay before Kamiya Keiyun.
He had no money!
Without money, how would he buy materials after leaving the village?
Before you continue