I recently noticed an interesting phenomenon: many beginners are asking why Bitcoin needs to be mined and why it can't be printed directly. Actually, there's a clever design behind this.

Since the birth of Bitcoin, it has been destined with a fate—only 21 million coins in total, never exceeding that. This number isn't arbitrarily set; it was carefully designed with mathematics by the creator in the white paper. Simply put, it uses the convergence principle of infinite series to make Bitcoin's issuance decrease each year, ultimately approaching the limit of 21 million.

Mining is essentially a calculation competition. Miners consume computational power to solve complex hash puzzles; whoever solves it first can earn the block reward and transaction fees. This mechanism cleverly ties network security to Bitcoin issuance—no one can create Bitcoin out of thin air; they can only obtain it through real computational work.

Looking at the previous halving events can help understand the power of this design. When Bitcoin was born in 2009, the reward per block was 50 BTC. Then, approximately every four years (after 210,000 blocks), the reward halved. In November 2012, it halved to 25, in July 2016 to 12.5, and in May 2020 to 6.25. Last year, in 2024, the fourth halving occurred, and now each block rewards only 3.125 Bitcoin. According to this schedule, Bitcoin will asymptotically approach 21 million but never reach it.

This decreasing issuance mechanism is very similar to gold, both having scarcity. Because the supply is limited and decreases each year, Bitcoin is called "digital gold." Factors like miners' computational power and transaction fees can even influence market funding rate fluctuations, as mining costs directly relate to miners' expected profits.

As for Bitcoin units, there are five from large to small: BTC (1 coin), cBTC (0.01 coin), mBTC (0.001 coin), μBTC (0.000001 coin), and the smallest unit is Satoshi, which equals 0.00000001 BTC. This smallest unit is still named after the creator, Satoshi Nakamoto—quite interesting.

In summary, Bitcoin's entire issuance system is a self-consistent ecosystem. No central bank, no institutional control—everything is maintained through mathematical rules and miners' computational competition. That's why some say Bitcoin is a truly decentralized currency.