I rely on learning to achieve immortality.

When Song Rou visited again, her face showed less hesitation and more determination.

She looked at Xu Zhou seriously: "Senior Brother, how long will it take to deduce the formula for the Clearing Obstacle Pill?"

Xu Zhou pondered for a moment and said, "I'm afraid it will take some time. After all, the Clearing Barrier Pill is quite difficult to refine, equivalent to a regular high-grade pill. It will probably take one or two years to deduce it properly."

Song Rou's expression relaxed: "Only a year or two? That's good."

"In addition," Xu Zhou reminded her, "Junior Sister, it's best not to practice any other cultivation techniques or secret arts before taking the pill, otherwise the effect of taking the pill may be affected, and the pill formula will have to be re-derived."

Song Rou thought for a moment and nodded, "Okay, that's no problem."

"What would you like as payment, senior brother? Just say it directly, and I'll agree to anything."

Upon hearing this, Xu Zhou looked at the other person carefully.

Decades ago, when he had just become an alchemist, the other party had invited him to join their alchemy room, and that scene seemed to be still vivid in his mind.

However, over the years, Song Rou's expression has gradually changed.

His eyes were calm, devoid of any of the tenderness he once possessed.

After thinking for a moment, Xu Zhou finally spoke: "Junior Sister, please grant me one request."

"What are your requirements?" Song Rou asked.

Xu Zhou said earnestly, "If Junior Sister is able to establish her foundation in the future and gain a place in the Hundred Herbs Hall, please put in a good word for me when I apply for the Foundation Establishment Pill in the hall."

Song Rou raised an eyebrow slightly: "You want the Foundation Establishment Pill?"

"We have to think about the future," Xu Zhou nodded and said.

Song Rou didn't ask any further questions.

She never even considered that Xu Zhou himself needed the Foundation Establishment Pill.

In her mind, even she had such difficulty in establishing her foundation, let alone Xu Zhou, who had a lower cultivation level and was older.

She also assumed that Xu Zhouqiu's Foundation Establishment Pill was prepared for his descendants or disciples.

After thinking for a moment, Song Rou finally nodded: "Okay, I promise you."

There are no small matters when it comes to Foundation Establishment Pills. Even if she becomes a Foundation Establishment Elder in the future, she may not be able to speak up for her at will, so this promise carries considerable weight.

At that moment, she made a vow of faith.

Xu Zhou did not stop her, allowing her to make such a vow.

This matter is of great importance, and even if the two people have a very good relationship, the terms must be clearly defined.

After Song Rou finished making her vow and extracted her essence and the aura of her cultivation technique, Xu Zhou also made the same vow.

Thus, the two reached an initial cooperation agreement.

Song Rou then took out a booklet and handed it to Xu Zhou: "These are my understandings of alchemy, all of which are recorded here. Perhaps they can help you speed up your deduction process."

Xu Zhou was overjoyed and immediately accepted the gift: "Thank you for the gift, Junior Sister."

"I hope you will succeed in your deduction soon, senior brother. Thank you in advance."

Song Rou did not linger and soon left in a hurry.

She is very busy right now, and she is carefully planning every moment in order to achieve foundation building as soon as possible.

Unless she achieves Foundation Establishment in the future, or gives up Foundation Establishment altogether, it will be difficult for her to stop and rest.

"We should deduce the prescription for her as soon as possible, lest this matter drag on for too long."

Although Xu Zhou's deduction of the elixir formula is not considered learning, it can still trigger a state of concentration, stopping the loss of lifespan by about 60-70%.

At the same time, with the notes and insights given to him by Song Rou, he can make further progress in alchemy.

This notebook does not contain any knowledge of inheritance, but the insights from Song Rou alone are enough to advance Xu Zhou's alchemy skills to a higher level.

It's unclear when the promise of the Foundation Building Pill will be fulfilled.

But this notebook alone was enough to benefit him greatly.

...

Xu Zhou's life remained largely unchanged; he continued to teach apprentices and refine elixirs as before.

However, he no longer sits in a corner to personally answer his apprentices' questions. Instead, he has opened a quiet room to focus on deducing the formulas for alchemy.

Song Rou's essence and cultivation technique must not be leaked; even his own disciples are not allowed to enter the quiet room.

As for the matter of taking on apprentices, that was left to Xiao Jingwen.

Since this disciple is using me as a cover, he should at least do something practical.

Anyway, Xiao Jingwen is now an alchemist, so teaching a few apprentices is more than enough for him.

Even if he wasn't a great teacher, Xu Zhou was already a top-grade alchemist and no longer needed to maintain his reputation for being a skilled teacher. He had plenty of people willing to take on apprentices.

Xu Zhou was then able to quietly retreat into seclusion in the quiet room.

In fact, the formula for the Clearing Obstacle Pill is not that difficult to deduce.

The reason it took him one or two years was that he had just become a top-grade alchemist and his skill level was still unstable. Furthermore, the Clearing Pill originated from medicine, and fusing the two into a single pill was quite difficult for him.

Song Rou's notes were indeed very helpful.

Even without the transmission of knowledge, the text is filled with many details that broaden Xu Zhou's horizons.

The thought that Song Rou had seen the complete lineage of alchemy rekindled his long-dormant heart, making him even more eager for the lineage he had not yet seen.

"Unfortunately, these traditions cannot be obtained through begging."

Xu Zhou suppressed his excitement and continued to absorb the knowledge from the notes, accelerating the integration of alchemy and medicine.

During this period, he rarely left the quiet room.

He only ventured out of seclusion a few times to give Li Pochen some pointers; the rest of the time, he stayed in the quiet room.

Six months passed in this way.

A minor incident occurred, which finally allowed Xu Zhou to emerge from seclusion.

Deacon Yuan has passed away.

This old deacon lived in Baicaotang for an unknown amount of time. Everyone thought he was nearing the end of his life, but he was still alive and well. Just when everyone thought he would live a long time, he suddenly passed away.

Xu Zhou had previously spoken with Deacon Yuan, but the conversation ended unhappily. However, he also knew that Deacon Yuan was merely following orders and had been very kind to him.

In the years that followed, he continued to write down his insights on alchemy and often visited Deacon Yuan's home to discuss matters with him, receiving much guidance in return.

Therefore, upon learning of this, Xu Zhou silently closed the book.

He temporarily put aside his calculations and went out of the pass to offer condolences.

Deacon Yuan has been with Baicaotang for many years, and has many disciples and juniors, as well as countless acquaintances.

When I arrived, the mourning hall was almost overflowing with people.

Those top-grade alchemists and late-stage Qi Refining cultivators, whom he rarely encountered, were now readily available. Even with Xu Zhou's current status, they had to step back.

After the memorial service, Xu Zhou met Yuan Ce, a former apprentice.

The other person has now grown into a composed young man, but his eyes are bloodshot, reminding Xu Zhou of what he looked like when he was young.

After catching up for a while, Yuan Ce finally spoke, "Before my grandfather passed away, he specifically instructed his juniors to leave you some things."

"Give me?"

Xu Zhou was momentarily surprised.

He hadn't expected that Deacon Yuan, with his wide network of connections, would actually leave something for him.

Yuan Ce nodded and took out a carefully sealed wooden box: "This was given to me personally by my ancestor. No one else has examined it before I hand it over to you, Alchemist."

Xu Zhou silently accepted it, and after a long while nodded: "Thank you."

"It's just my duty, Master Xu, please take care."

Back in his cave, Xu Zhou entered the quiet room and carefully opened the wooden box.

There were no large items inside the wooden box, only several books lying quietly inside, with a letter sealed on top.

Upon opening the letter, it was found to be written in the style of Deacon Yuan during his lifetime:

Brother Xu Zhouxian:

Seeing this letter is like seeing you in person. I am about to depart, and I have little more to say.

Your talent is mediocre, yet you remain steadfast in your commitment to alchemy; such a heart is rare, much like mine in my youth. The sect's legacy is beyond my control, and I regret this.

I am now presenting you with several volumes of my life's work, all derived from a century of research. While they may not be of the orthodox lineage, they can still help you avoid some detours.

There are different paths to spiritual practice. Your path lies in the two words "constant mind," and by practicing it, you may go far.

It's already a rare privilege to have met you. May we both take care of ourselves from now on.

—Retained by Yuan.

Xu Zhou remained motionless for a long time after reading the letter.

After a while, he folded the letter and carefully placed it into the wooden box.

He then took out the first book from the wooden box, carefully opened it, and began to study the scriptures on it.

The room fell silent for a moment.