Author: Xiaobing, Deep Tide TechFlow
Recently, I've been swamped by posts about "Letters to A-Ma." With a Douban score of 9.1, it's the highest-rated domestic film of the 21st century, a dark horse at the May Day box office, still gaining momentum even after breaking the 200 million yuan mark.
The film tells the story of a letter delayed by half a century. In the Chaoshan region during the 1940s, a man went to Southeast Asia (Nanyang) to seek a livelihood, leaving behind his young wife and three children. He died in a foreign land, and the daughter of the innkeeper, out of a debt of gratitude, spent 18 years writing letters and sending money to his wife under his name.
The crumpled pieces of paper in the movie are called "Pí" in the Teochew dialect. The letters and money sent home by overseas Chinese together are called "Qiaopi." It sounds rustic, but if you know a bit of financial history, you'll understand:
This thing was one of the most magical cross-border financial networks in human history. It emerged a hundred years before SWIFT and a hundred and fifty years before blockchain. Entirely privately operated, peer-to-peer, without central clearing, and operating across sovereignties, it supported half of China's international balance of payments in modern times.
Its entire credit foundation was based on a Teochew saying: "The letter is bigger than life."
A Forgotten Financial Infrastructure
First, look at a few numbers to understand how remarkable this thing was back in the day.
The origin of Qiaopi can be traced back to the mid-19th century. The earliest surviving physical Qiaopi found so far is from 1881, but its actual operation likely started earlier. It continued functioning until 1979, when this business was fully integrated into the Bank of China system, operating for over a full century.
There are about 170,000 archived items, with Guangdong accounting for 160,000 (over 100,000 from the Chaoshan region) and Fujian around 10,000. And these are just the survivors. At its peak, hundreds of millions of dollars flowed into China annually through Qiaopi channels. During the War of Resistance against Japan from 1937–1945, remittances through Qiaopi accounted for over 50% of China's foreign exchange income, holding up half the sky.
Tan Kah Kee alone, relying on Qiaopi to send money home, founded the Jimei Schools in 1913 and Xiamen University in 1921. A complete modern university was funded by one crumpled letter after another.
What's even more astounding was its operating mechanism.
For most of the time before 1979, the operation of this network almost entirely did not rely on any government endorsement, any central bank, or any official clearing system. No SWIFT, no central bank foreign exchange controls, no cross-border interbank accounts—nothing.
What did it rely on? Three things: Shui Ke (water couriers), Pi Ju (Qiaopi agencies), and something called credit—the very thing most lacking and most precious in today's finance industry.
Shui Ke: The Human Version of On-Chain Nodes
In the earliest days, there were no Pi Ju agencies; it was all handled by "Shui Ke."
Shui Ke was a profession, specifically those who traveled back and forth between Nanyang (Southeast Asia) and Chaoshan or Southern Fujian on red-headed ships. They would go to mines, rubber plantations, and docks in Nanyang, visiting fellow villagers door-to-door to collect letters and money, which they then tucked into their belts. The money was literally strapped to their bodies, and upon returning to China, they would deliver it door-to-door to the recipients.
It sounds primitive? But this mechanism had several features that would make modern financial experts exclaim:
First, it was peer-to-peer. No intermediary clearing banks. From the moment the sender handed the money to the Shui Ke until the recipient received it, this money did not pass through any bank account or any sovereign monetary system.
Second, it was identity-verified. The Shui Ke were usually fellow villagers who knew both parties. This was a form of identity authentication more reliable than SSL certificates—you could run, but you couldn't hide your temple. A Shui Ke knew everyone in a Teochew village—how many family members, which alley they lived in, the entire kinship network.
Third, its default rate approached zero.
This point deserves special mention. From the 19th century to the first half of the 20th century, Shui Ke had no collateral, no insurance, no legal recourse. They often carried the entire savings of dozens of households from a single village. Converted to today's purchasing power, a single trip could be worth millions of RMB. If a Shui Ke ran away, no one could catch him, let alone make him pay.
But they just didn't run.
Why? Because the essence of this business was credit as the sole collateral. If a Shui Ke ran off just once, all his relationships with fellow villagers on both sides—in Chaoshan and Nanyang—would instantly evaporate. He would be finished in the Chinese community for life. The cost of being permanently ostracized by the entire community was far heavier than any legal punishment.
Pi Ju: From P2P to a Network of Financial Institutions
As the Shui Ke era continued, some people began to professionalize the business, leading to the emergence of Pi Ju—specialized Qiaopi agencies.
The emergence of Pi Ju upgraded Qiaopi from "individual peer-to-peer" to an "institutional network." But unlike modern banks, Pi Ju remained privately owned, family-run, and networked, with one end in Nanyang and the other in the hometowns, woven together by relationships and family credit.
How intricate was its fund flow? Let's break it down:
Step one: Overseas Chinese A walks into a local Pi Ju in Nanyang, hands over 100 Thai baht, and tells the agency to send it to family member B in Chaoshan.
Step two: The Pi Ju immediately issues A a "Pi" (a letter combined with a remittance slip) based on the exchange rate. The amount written on it might be in Hong Kong dollars or silver dollars, but almost never in Thai baht.
Why not Thai baht? This is one of the smartest aspects of Qiaopi. Early transnational Pi Ju agencies long used Hong Kong dollars as the settlement currency, because the Hong Kong dollar was pegged to the British pound, had good liquidity, and was recognized throughout Southeast Asia. This was equivalent to the modern East Asian Chinese community spontaneously choosing a supra-sovereign settlement currency.
It sounds somewhat like the logic behind the demand for USDT/USDC in today's crypto circles—cross-border, avoiding exchange controls, deep liquidity, and recognized by all participants.
Step three: The Nanyang branch of the Pi Ju sends the letter and remittance instructions back to the corresponding Pi Ju in Chaoshan by ship, but the money doesn't necessarily physically travel back.
This is key. A mature Pi Ju would establish long-term relationships with import-export merchants in Nanyang. The money sent by Nanyang Chinese to their hometowns (Nanyang → Chaoshan direction) could be directly used to pay for goods imported from China (Chaoshan → Nanyang direction). The cash flows in the two directions offset each other, meaning only a small portion of the net difference might need to be transported across borders.
This mechanism has a trendy name today: "netting." The SWIFT system handles trillions of dollars in transactions daily, essentially doing this. The Pi Ju were doing it 100 years ago.
Step four: Upon receiving the instructions, the Chaoshan Pi Ju dispatches "Pi Jiao" (couriers) to make door-to-door deliveries. Pi Jiao often walked dozens of kilometers, visiting each household, reading and writing replies for illiterate wives and mothers-in-law, confirming receipt. Then this "return Pi" would travel back along the same route to Nanyang, completing the entire transaction loop.
The entire process involved no bank accounts, no government regulation, and no central clearing system, yet it ran steadily for a century.
Secret Pi and the Dongxing Remittance Route
The most fantastical stories of Qiaopi occurred during the war years.
In 1939, the Japanese invaders occupied Shantou, completely severing the normal Pi Ju remittance routes. Half a million families in the hometowns faced the imminent cutoff of their livelihood.
At this point, the overseas Chinese did something that would go down in history: they carved out a new underground remittance route.
Goods were shipped from Nanyang by boat to Haiphong, Vietnam, then entered China via the Dongxing checkpoint on the Sino-Vietnamese border. From there, porters carried them basket by basket into Guangxi, eventually making their way back to the hometowns in Guangdong. This route was called the "Dongxing Remittance Route," and at its peak, annual remittances still reached tens of millions of yuan.
While the sovereign financial system collapsed amidst the flames of war, the private financial network temporarily built an entirely new channel.
Even more extreme were the "secret Pi" (An Pi). To evade interception by Japanese troops and later the Kuomintang, overseas Chinese used coded language in their letters to indicate remittance amounts. "One bag of rice" represented a certain number of silver dollars; "five salted fish" represented a certain amount of Hong Kong dollars. This entire coded system operated in the minds of Shui Ke and Pi Jiao; even if the enemy intercepted the letters, they couldn't decipher them.
During the War of Resistance, Zhou Enlai personally wrote a letter of thanks from Wuhan to Tan Yixi, an overseas Chinese in Cuba, because this Chinese compatriot had hidden donations for the anti-Japanese war within Qiaopi and directly delivered them to the Wuhan office of the Eighth Route Army.
What would this be like in today's terms? It's equivalent to a scenario where the US dollar is sanctioned, SWIFT is cut off, and bank accounts are frozen, yet overseas Chinese, relying on a private consensus network, could still deliver tens of millions of dollars worth of funds annually to designated recipients.
Isn't this "censorship-resistant transactions," "off-ledger accounting systems," or "private stablecoin clearing networks"? But its inventors didn't know these terms. They only knew: Grandma at home is waiting for money, the children need to eat, and the country is at war.
A Financial Miracle We May Never See Again
Qiaopi, blockchain, and SWIFT represent different interpretations of credit.
SWIFT is cooperation based on state credit. It is built upon sovereign currencies, central banks, commercial banks, and regulatory coordination. Its strength relies on the stability of the entire international order. Crypto is the credit of mathematics and code, attempting to replace trust in people and institutions with cryptography and consensus algorithms.
And Qiaopi?
The essence of Qiaopi is the credit of clans, hometowns, human connections, and oaths. It had no mathematics, but it had family genealogies, accents, and hometown dialects. Its core engine was a cultural consensus where defaulting meant "social death."
This is what modern finance needs the most: credit itself as collateral.
All so-called "innovations" in today's finance industry essentially aim to compensate for the disappearance of this very thing: collateral, guarantees, regulation, insurance, legal recourse, credit scores, KYC, AML. We use increasingly complex systems in an attempt to recreate that simple state where "a Shui Ke carries a village's money in his belt and still doesn't run."
The weight of this difficulty can only be truly felt through specific people.
During the Guangxu era, Yang Jie, a Chinese immigrant in Thailand, sent a Qiaopi home containing only 10 characters: "Upon receiving this letter, immediately redeem my daughter and bring her home." Remittances had been interrupted at the time, forcing his wife to sell their daughter. After learning this, his heart was torn with grief. He urgently sent 50,000 yuan home, able to write nothing more than "immediately."
Chen Lianyin, a female street vendor in Singapore, struggling to survive herself, heard her mother had injured her foot. She scrimped and saved to send money home: "Mother, due to constant lack of food, you injured your foot, unable to walk without a cane. Hearing this, I cannot help but weep." She called this a sin against familial duty.
The last Qiaopi the grandmother received in the movie reads: "Although Siam (Thailand) is far, the heart has its abode. Even if separated by distance, take care and be safe—that itself is reunion."
The amounts in Qiaopi were mostly 5 HKD, 10 HKD, 50 HKD—just a little bit sent with each letter, but year after year. Over a century, generations of Chinese, tens of thousands of Pi Ju agencies, hundreds of thousands of Shui Ke and Pi Jiao, delivered these small sums and words of peace across wars, revolutions, turmoil, and famines, right on time to the doorsteps of homes in Chaoshan, Southern Fujian, and Wuyi counties that they might never have the chance to return to in their lifetime.
The engineering difficulty of this feat has yet to be replicated by any modern payment system under equivalent conditions.
And its entire tech stack was simply: a red-headed ship, a Shui Ke with a familiar accent, a faded belt, and the words "The letter is bigger than life."
All the grand narratives in the crypto space over the past decade—decentralized cross-border payments, permissionless financial networks, global clearing bypassing SWIFT, private stablecoins, credit as collateral—have already happened in those long-forgotten villages along China's southern coast, in the hands of those illiterate grandmothers and mothers-in-law, around the waists of those uneducated Shui Ke, for a full hundred years.
This is a story about the most simple yet magnificent essence of the word "credit," one we may never see again.
Dedicated to all those who ever wrote a word, signed a name, entrusted a sum, or received a payment on those yellowed pages.
And to all those still trying to rebuild such networks of credit today.
