OSAKA--Littering has long soiled the bustling Dotonbori district here as tourists who enjoyed takoyaki and other local specialties often just tossed away the plastic trays and sticks. But now ...

At Daruma, a famed restaurant in Osaka’s busy Dotonbori district, the No. 1 rule has been: “No double-dipping.” Now, the rule is: “No dipping. Period.” The restaurant serves ...