The moat was dug for cargo, not for defence. The Hachiman-bori at Ōmihachiman is a channel connected to Lake Biwa, cut so that boats travelling the lake would come into the castle town instead of passing it. White-walled storehouses stand along the water, and turning inland toward Shinmachi-dōri brings you among the main houses of the Ōmi merchants, so the waterside and the merchant streets can be walked as one route.

Ōmihachiman was designated an Important Preservation District in April 1991, and restoration of the townhouses continues, with new businesses opening in them. The Tōkaidō line reaches Kyoto in about thirty-five minutes. That combination is unusual: a commuter town within half an hour of a major city that still has a working canal running through its old quarter. The Ōmi merchants traded in other provinces and kept their main houses at home, which means the substantial buildings along these streets were not where the money was made. They were where the family returned.

Digging a moat is a device for stopping boats that would otherwise go by. Make a cul-de-sac off the main water route and arrange matters so that cargo can only be handled inside it, and the town stops being somewhere the trade passes and becomes somewhere it calls. As a method of recovering the cost of excavating a channel, it was about as reliable as such schemes get, and the proof is standing along the bank in the form of storehouses. Boats stopped using the moat long ago, and the buildings that the arrangement paid for are still here, now holding restaurants and shops.