The man who built this town was dead within ten years, ordered to cut his own belly open by the uncle who gave him the land. His castle didn’t last much longer. It was pulled down, its stones left to the weeds on the hill. What survived was the ditch he’d dug around it. Four centuries on, that ditch is the finest thing in town, and the castle it was meant to protect is a paragraph on a plaque.

It has a name, Hachiman-bori, and the town that grew along it is Omihachiman, out on the flat eastern shore of Lake Biwa. It outlasted the castle for a plain reason: it stopped being a moat and turned into a canal. In 1585, Toyotomi Hidetsugu had it cut all the way down to Lake Biwa, then required every boat crossing the water to turn into the canal and stop in the town before going on – a checkpoint dressed as a harbor. Within a generation the moat was a trade route, and the families along its banks got rich.
Hidetsugu didn’t live to see much of it. He was the nephew and, for a while, the chosen heir of Toyotomi Hideyoshi, the warlord who would finish unifying the country a few years later, and at eighteen he was handed this corner of Ōmi to govern. The arrangement didn’t last. When Hideyoshi had a son of his own, the nephew went from heir to liability, and in 1595 he was accused of plotting treason and ordered to take his own life. The canal he’d dug barely noticed.

The families along it became the Hachiman merchants, a branch of the Ōmi shōnin. Over the next two centuries, they grew into some of the shrewdest traders Japan ever produced. By the 1700s they were peddling mosquito nets and tatami and hemp cloth from one end of Japan to the other. With them they carried a rule, one that’s still quoted in business schools today: sanpō yoshi – good for the seller, good for the buyer, good for society. Their reputation for fair dealing brought the business in, and the money came home to this canal.







