Japan had known for a decade that it would host this year’s Rugby World Cup. But only in the final months before kickoff did the city of Kobe grasp what it was in for. Some 36,000 fans from Ireland, England, Scotland and South Africa were on their way. And—these being rugby fans—they would be dangerously thirsty.

The Kobe tourist board needed to get the word out. At a seminar in May, it told restaurants, bars, and hotel operators to brace themselves for a run on all liquids hoppy, malty and cold. As it wrote on one fact sheet:...