I Want Your Brain

I am not a zombie, and I am not Cheng Xin. I am the founder of this website.

Let me tell you why I started it.

University Experience

I graduated from one of China’s 985 universities. After I got there, I realized all my classmates were also from a 985 university. What a coincidence!

In China, getting into a 985 university is not easy. As a rough simplification, you can think of it as outperforming 98.5% of people. That is not a precise definition, but it is enough to say one thing: people who get into these schools are not ordinary.

During university, however, I did not feel this very strongly.

Everyone around me seemed similar. We attended classes, took exams, worked on projects, and discussed problems together. They just looked like ordinary classmates.

Entering Society

After graduation, I entered a broader social environment and met people from many different backgrounds.

Only then did I gradually realize that many classmates who once seemed ordinary were not ordinary at all. Their strength was not just that they knew more facts or had better exam results. It was that they approached problems differently.

When they faced a complex problem, they first looked for structure instead of rushing toward an answer.

When they learned a new field, they focused on core concepts, boundaries, and dependencies instead of memorizing conclusions.

When they expressed an opinion, they kept asking whether the assumptions were valid, whether the logic was complete, and whether counterexamples existed.

They made mistakes, felt confused, and took detours like everyone else. But in their minds, there was a learning system and a set of thinking habits built through long practice. These things do not always appear on a resume, and they cannot be fully captured by a degree, but they keep showing up in work, study, and life decisions.

They are what we call xueba: top students who really know how to learn.

The Regret

I wanted these classmates to share what was inside their minds.

Not just how to solve a particular problem or how to use a particular technology, but how they understand problems, build knowledge systems, judge whether an explanation is reliable, and learn complex topics from scratch.

In particular, I wanted students from places with fewer educational resources to see these ideas.

In the past, if a student was not in a good school, a good city, or surrounded by excellent teachers and peers, it was hard to access these hidden learning methods. Today, the internet makes information distribution much easier. If someone is willing to write and explain carefully, these experiences can cross regions, schools, and family backgrounds to reach more people who truly need them.

But in reality, many of my classmates went to work at different companies after graduation and became corporate workhorses.

The more general and educationally valuable parts of what they know often remain unorganized and unseen by students who could benefit from them.

That felt like a real waste.

Collecting Xueba Brains

So I started Kuaiyizhi.

I want it to become a place where the knowledge, methods, and thinking patterns of strong learners can be organized into clearer, more systematic, and more understandable forms.

The courses here should not be piles of reference material, nor should they simply copy textbook tables of contents. We care more about questions like:

• How would someone who truly understands this topic explain it to a beginner?
• How would a strong learner break down the relationships between concepts?
• How would an experienced person warn readers about common traps?
• How would a rigorous thinker distinguish conclusions, proofs, intuition, and applications?
• How would someone who wants to help others explain the path they once walked?

I will go find, or more accurately beg, my classmates. I will also look for people who truly understand a field and invite them to write and teach according to their own way of understanding. The goal is not to produce cold standard answers, but to let them explain how they learned, how they thought, and how they eventually understood.

Keeping Costs Low

After graduation, I also used some well-known online education websites to learn things. But I found them expensive. A course could easily cost hundreds or thousands of yuan.

I also had a colleague who spent tens of thousands of yuan on a training program for just a few months.

Kuaiyizhi can operate at a relatively low cost largely because it was not built from the beginning by a commercial team with a large budget.

Many of these courses were written by people I know personally: classmates, friends, and people who understand their fields. Most of them did not charge me. They were willing to share what they know, what they have finally understood, and what they learned after taking detours, so I could organize and publish it here.

In terms of direct financial cost, that makes the site quite inexpensive to run.

But that does not mean there is no cost. The real cost is time.

After a course is written, it still needs to be checked, restructured, edited, and corrected. Some parts need to become easier to understand. Some need examples. Some concepts need to be verified again for rigor. These things cannot all be finished in one burst of enthusiasm.

More importantly, we need feedback from readers.

Where is the explanation unclear? Where does the course move too quickly? Where is there a mistake? Where could there be a better explanation? These things often come from people who actually read the course carefully. A course becomes better not because it was perfect from the beginning, but because someone read it seriously, pointed out problems, and then we slowly fixed them.

Much of this work is done by squeezing time out of evenings, weekends, and ordinary gaps in life.

So course updates on Kuaiyizhi may be slow, and fixes may also be slow. If you report a problem and it is not addressed immediately, please do not worry too much. We will try to see it, record it, and work on it, but the pace may not be as fast as a mature commercial product.

Slow work can produce careful work.

Even the website itself cannot guarantee that it will never fail. Many large internet companies build services with very high availability. That gives people a feeling that life should work the same way: everything must be fast, nothing can pause, and everything must always be online.

But I do not want Kuaiyizhi to bring that kind of tension to readers.

I hope that when you come here, your pace can slow down a little and your mind can relax a little. Learning should not feel like being pushed forward by a system or chased by a progress bar. Learning should be something joyful: today you understand a little more, tomorrow something else becomes clear.

If Kuaiyizhi is sometimes slow, please understand it this way: with limited time, we are trying to do a long-term thing carefully.

What We Believe

I believe the most valuable part of education is not only knowledge itself, but the method of acquiring knowledge.

A formula can be memorized. A concept can be looked up. An answer can be searched. But how a person develops problem awareness, keeps learning, faces confusion, and turns fragmented information into a personal knowledge system is harder to obtain and more worth sharing.

Kuaiyizhi wants to make these less visible things as clear as possible.

It may not change everything immediately, and it cannot cover every field. But if one student takes fewer detours because of a course here, if one learner suddenly understands a long-confusing idea because of an explanation, or if one person rebuilds confidence in learning by seeing how others think, then this website has meaning.

Closing

I started Kuaiyizhi because I hope knowledge and methods that once stayed only in a few people’s minds can be seen by more people.

Excellence should not serve only a small number of companies, and knowledge should not remain inside a small number of circles.

If the internet makes sharing easier, we should use it seriously and pass on what is truly worth passing on.

That is where Kuaiyizhi begins.

If it can help you, that would be my greatest honor.