Have you ever wondered why in late ancient China, the currency suddenly shifted from "one tael of silver" to "a silver dollar"? The logic behind this is more interesting than you might imagine.

Back in the late Qing Dynasty, the debate over whether to use "liang" or "yuan" was heated across the government and society. But in the end, the winner emerged—the silver dollar. This wasn't a decision made by some official on a whim; it was purely a market vote with feet. If you insist on circulating one tael of silver, consumers won't go for it—they'd rather collect it and make jewelry. Isn't that troublesome?

Why did this happen? There are two main reasons.

**First, the exchange rate issue.**

The standard silver dollar worldwide originates from designs dating back to Newton's era. One silver dollar has a clear value, eliminating the need to calculate exchange rates like a game of mahjong. Imagine Shang Yanlin going out to do business with one tael of silver—his trading partner wouldn't even know how much his silver is worth. In a time without calculators, just converting this could drive people crazy. The silver dollar directly avoids this hassle.

**Second, transaction costs.**

What was the purpose of ancient money shops? Simply put, they were currency exchange stations. Why? Because the purity of silver varied across regions. If you saved up 100 taels of silver in Baoding and took it to Guangzhou for procurement, the merchants there wouldn't recognize it—they wouldn't know how much silver content your silver has. You might get scammed at every turn. So, you had to go to a local money shop to exchange it for "Guangzhou silver" to use it.

Has anyone thought about creating a standard silver? Theoretically, yes. But the problem is: you need to specify weight; otherwise, trade is still impossible. Even more critically, who guarantees that the weight won't shrink? Someone might secretly scrape a little bit off the edge of a silver ingot—what do you do then? Lawsuits?

Silver dollars are different. Their standards are extremely strict. Fixed weight (one silver dollar weighs 7 qian 2 fen, 26.7 grams), fixed silver content (89%), and even the silver content of Qing Dynasty silver dollars is the same as European silver dollars—so one-to-one exchange can happen without worries for either party.

This is actually an inevitable evolution of currency. It wasn't a top-down policy push but a rational market choice that naturally eliminated inefficient old schemes. From certain perspectives, this logic remains unchanged even today.