Basic Knowledge Learning: Why did Satoshi Nakamoto create Bitcoin?

In the process of creating Bitcoin, Satoshi Nakamoto invented blockchain technology, which is the underlying technology derived from Bitcoin. So, why did he want to create Bitcoin? What problem did he want to solve?
Currently, Bitcoin is often referred to as a "cryptographic digital currency," and people tend to pay a lot of attention to the word "currency" in it. In fact, Bitcoin does not possess the characteristics of the legal tender of various countries; it is merely a special commodity in digital form. The current market price of Bitcoin and its volatile fluctuations also influence people's perceptions of it, with people comparing it to various investment and speculation targets such as gold and tulips.
But if we go back to the moment Satoshi Nakamoto created it, we would see that the emergence of Bitcoin stemmed from a technical problem that tech geeks wanted to solve: "How to create something with cash-like properties in the digital world?" The title "Bitcoin: A Peer-to-Peer Electronic Cash System" reflects the problem Satoshi Nakamoto wanted to solve: he wanted to create electronic cash that could be used in the digital world, allowing for peer-to-peer transactions without the need for any intermediaries.
Let's compare. In the physical world, a person can give cash bills to another person without the need for intermediaries such as banks, payment institutions, or witnesses.
However, because digital files are replicable, the copied electronic files are identical, we cannot simply use a digital file as a representation of value in the digital world. At the same time, the amount of money we have in payment institutions does not have digital files like banknotes to represent it; money is merely a record in a centralized database.
In the digital world, when a person wants to transfer cash to another person, the involvement of an intermediary is necessary. For example, the process of transferring money through Alipay is: Alipay deducts a certain amount from one person's account record and adds a certain amount to another person's account record.
In the digital world, creating a decentralized digital cash system that does not require intermediaries has always been a challenge. Since digital files can be perfectly copied, how can one prevent a person from spending the same amount of money twice without a centralized database to keep records?
This is known as the double spending problem. Before Bitcoin emerged, the primary electronic cash systems we were familiar with (such as PayPal, Alipay, etc.) relied on centralized databases to avoid the double spending issue, and these trusted third-party intermediaries were indispensable, as shown in Figure 2. However, on the path of eliminating intermediaries or decentralized electronic cash, many tech enthusiasts have been making various attempts, but they have not been able to achieve final success.
By 2008, Satoshi Nakamoto had drawn on and synthesized the achievements of predecessors, particularly those of the group commonly referred to as cypherpunks, improving on various forms of centralized and decentralized electronic cash, and with unique innovations of his own, created Bitcoin, a peer-to-peer electronic cash system that solves the double-spending problem without the need for intermediaries. In particular, the Bitcoin electronic cash system is both decentralized and intermediary-free:
Electronic cash between individuals does not require the intervention of a trusted third-party intermediary, which is decentralization.
The issuance of this electronic cash currency does not require a centralized institution, but is completed through code and community consensus, which is decentralization. It is important to note that the "cash" in this "electronic cash" does not refer to currency; it is merely borrowed to represent value in the digital world during the problem-solving process. This is stated for the sake of understanding, as in reality, the most common representation of value is cash.
Initially, Bitcoin, the electronic cash used to represent value, had no price. The Bitcoin system was merely a theoretically feasible system, a technological toy that solved a problem. On May 22, 2010, a programmer exchanged 10,000 Bitcoins for two Papa John’s pizza vouchers on an online forum, marking the first time Bitcoin had a fair price: 10,000 Bitcoins were valued at $25. To commemorate this day, every May 22 has become a holiday in the blockchain world—Bitcoin Pizza Day.
Since then, Bitcoin has never been a currency, but it has gradually gained value and price. The price of Bitcoin is determined in free market trading and has continuously and repeatedly experienced significant fluctuations. However, whether it dropped by half from an early price of 1132 dollars or rapidly rose to nearly 20,000 dollars at the end of 2017, only to drop to one third within a few months, the Bitcoin system and its underlying blockchain technology have remained stable.
The Bitcoin electronic cash system designed and coded by Satoshi Nakamoto has been in operation for nearly a decade. The Bitcoin system has transformed from a technical toy into a system that operates almost perfectly, and it appears that it will continue to operate stably for a long time.