In the world of digital money, we often hear statements like "how much Bitcoin is in my wallet." However, this statement is actually inaccurate. In fact, the "wallet" applications or hardware we refer to do not store any Bitcoin. This seemingly contradictory phenomenon actually reflects the essence of digital asset ownership.

Let's understand this concept through an analogy: comparing the relationship between a physical Wallet and a bank card with a password. A physical Wallet contains actual cash, and the Wallet and the money are physically bound together. If the Wallet is lost, the cash inside will disappear as well.

So, where exactly is Bitcoin stored? All Bitcoins exist only on the globally shared, immutable public ledger - the blockchain. A Bitcoin 'wallet' is actually a key management tool, rather than a container for storing Bitcoins. Its main function is to generate and manage two important elements:

1. Public Key: Similar to a bank card number, used to generate your receiving address. You can safely share it with others to receive payments.

2. Private Key: This is the real key point. It is equivalent to a combination of your bank card password and signature. The private key is the only proof in the universe that you own the assets corresponding to a certain address. Whoever holds the private key has complete control over these Bitcoins.

Therefore, the so-called 'transfer' does not physically move Bitcoin from one Wallet to another. In fact, this process involves you signing a command with your private key and broadcasting to the global ledger: 'Please transfer the funds recorded in my name to the designated address.'

This is why people in the cryptocurrency community often say 'Not your keys, not your coins.' Storing Bitcoin on an exchange is like giving both cash and passwords to a bank for safekeeping. Only when you hold your own private keys do you truly become the complete custodian of your digital assets.

Understanding this concept is crucial for participating in the digital money world. It not only helps us better protect our assets but also deepens our understanding of one of the core principles of blockchain technology. In this decentralized new world, everyone can become the true owner of their wealth, but this also means we need to take on more responsibility to protect our digital assets.