A brother asked, can you explain in a simple and understandable way what Bitcoin is? My model is very simple, even children can understand it, and it can quickly help people understand what Bitcoin is within 10 minutes. On a secluded island, there are 100 people living, each with their own division of labor. Everyone produces their own food and exchanges it with each other when needed. These 100 people felt that exchanging food was too troublesome, so they invented bookkeeping. Only two people know about this kind of bookkeeping, for example, I owe you 2 chickens and you owe me 10 fish. Later, someone found that keeping separate accounts was too troublesome, so they invented using an item instead of food, such as a special stone representing the price of one chicken, which cannot be forged. This is the earliest currency. With the increasing frequency of exchanges, some people suddenly realized that they did not need currency and could establish an institution specifically for trading goods and recording transaction data. Bookkeeping by dedicated personnel and supervision by others. This is the earliest bank. The problem now is that someone is secretly changing the data (which is inflation), and this is life-threatening. The key point is that later on, someone invented another accounting method: instead of assigning a dedicated person to keep accounts, each of the 100 people on the island had a ledger. Every time two people make a transaction, the other 98 people on the island are called over to witness the transaction, and each person records the transaction on the ledger. In this way, everyone on the island has an identical account book, and each transaction is recorded once. If someone's ledger is lost or there are no records, the ledger with the highest number of people shall prevail. This is distributed accounting. If you want to forge, you have to call over 50 people on the island to change the data together, which is a 51% attack. There are two problems now: 1. It's too troublesome to call 98 people over for each transaction 2. I have to go over and keep track of other people's transactions, why should I? First, it was impossible in the agricultural era. Later, someone invented the Internet. Instead of going there, you can download an app and keep accounts online. The second question is that every time you keep an account, you may receive a corresponding commission reward, which is paid by the person making the transaction. This is called mining. This is the simplest Bitcoin model. (Of course, this does not include models of deeper financial support and monetary systems)