Fable
Fake commands and fake numbers
Old Han ran a canal shipping freight house by the canal, specializing in north-south cargo transshipment. Every day the freight house received shipping orders sent from upstream docks—item name, quantity, destination, consignee, all four columns filled in. The clerks booked boats, loaded cargo, and collected payment according to the shipping orders, and for over a decade nothing major ever went wrong.
One autumn, the goods firm received a shipping order from Yangzhou with a line slipped in: "Send all silk to Jiangning Prefecture, not Suzhou." The clerk followed it, and all three boatloads of silk went to Jiangning. The consignee in Suzhou waited in vain and brought a complaint to the chamber of commerce. Old Han traced it and found that a dockworker at the Yangzhou wharf had slipped it in amid the confusion, having been paid by another goods firm.
Old Han set a rule: when a cargo list comes in the door, a literate clerk reviews it first; anything containing instruction words such as "void," "redirect," or "do not send" is held on the spot, circled in red, and reported. Once the rule was established, fake instructions never came through again.
After two peaceful months, trouble happened again. Three consecutive batches of medicinal materials sent to Jinan did not match in weight when they arrived—the shipping document said two hundred jin, but the boat had only one hundred twenty. Old Han investigated for nearly a month and found the source: an accountant at an upstream dock quietly reduced the weight by forty percent each time he filled out the medicinal materials shipping document. What he changed was the number; he did not touch a single instruction word—the product name was correct, the destination was correct, the sender was correct, and there was neither “void” nor “redirect.” The document-reviewing clerk checked only the words, and the tampered number was impossible to see at all.
Old Han looked at the two kinds of problems together. The first, 'inserting fake commands': the shipping order directly contained instructions telling the clerk to dispatch the boat according to a fake command on the spot—the signal was obvious and could be caught by the wording alone. The second, 'changing real numbers': do not touch the instruction wording, only the data—the item name was right, the destination was right, the shipper was right, only the weight was short by a chunk. The clerk dispatched the boat, calculated fees, and notified the recipient according to the fake numbers. Every step followed the rules, but every step stood on fake numbers.
Old Han added a step to the trading house: digital verification. The weight and quantity on every waybill had to be cross-checked against the dock's outbound records; if they did not match, the ship was held and marked "pending verification." For high-value goods like herbs and raw silk, a third-party weighing certificate was also required.
At the year-end chamber of commerce audit, the inspector asked Old Han how he prevented fake goods slips. Old Han laid out two procedures: the first was word interception, catching smuggled fake commands—changing the shipping destination wouldn't get past the gate. The second was numerical verification, checking tampered data—skimming off the weight to pocket the difference wouldn't get past the scale. After reviewing the records, the inspector said: most goods firms guard only one gate; you're the first to guard both.
Later, Old Han summed it up for his apprentice: a fake command is like someone slipping an extra page into a message book that says, "Everything said before doesn't count"—the extra thing can be seen at a glance. A fake number is like someone using a fine pen to alter a few digits in the ledger—the surface looks exactly the same, but every deal you make based on that wrong number, the ship is loaded with less, the money collected is less, and the consignee waits for nothing, and all the loss is yours.