Recently, whether in Zhihu or in the headlines, there has been controversy over the concept of the total number of bitcoins 21 million. Many people think that the total number of things that can be divided infinitely is definitely more than that, while some people think that it is 21 million.

Why do many people think that the total number of bitcoins is definitely more than 21 million? Because now many people know that a bitcoin can be cut into 100 million copies. In fact, the smallest unit is not a bitcoin, but a Satoshi. One bitcoin= 100 million Satoshi. That's why people think that the total amount of bitcoin is not 21 million.

As for such a debate, I personally think it is right that the total number of bitcoin is 21 million. We can first understand from the principle of bitcoin. What is bitcoin? This time we use abstract concepts to explain that the essence of bitcoin is actually a special solution generated by a bunch of complex algorithms. A special solution is one of the infinite (in fact, bitcoin is finite) solutions that can be obtained from the equations. Every particular solution can solve the equation and is unique. In the metaphor of RMB, bitcoin is the serial number of RMB. If you know the serial number of a note, you have the note. The process of mining is to constantly seek the special solution of this equation system through a huge amount of calculation. This equation system is designed to have only 21 million special solutions, so the upper limit of bitcoin is 21 million. I hope you can understand that the real form of bitcoin is an encrypted serial number, like a bar code, rather than a coin.

The second is that I hope you can distinguish between unlimited total amount and wireless division, which are two different concepts. For example, I have 100000 bitcoins. No matter how the rest of the other parts are divided, I have 100000 / 21000000 of them. I can't be more bitcoins than I because someone else has divided a bitcoin into tens of thousands of shares, right? I'm not going to be over 100000 / 21000000 just because I've split my 100000 bitcoins into 100 million shares, right? Different from the traditional currency, it can be printed infinitely, so when the country prints a large number of banknotes, the currency in your hand will depreciate, which is why bitcoin is recognized by people, that is, it can't be issued infinitely.

In a word, remember that all assets are calculated in proportion.

(2021-4-12)