Japanese Highballs Celebrate Simplicity

Highballs, the category of drinks served in their namesake Highball or Collins glass, consist of a base spirit topped with sparkling water, tonic or a nonalcoholic mixer like ginger ale. Think scotch and soda, gin and tonic, Jack and Coke, Seven and Seven—all Highballs. Whiskey. Soda. Ice. What could be simpler? 

But with such an austere formula, perfecting each ingredient is key to achieving balance, prompting bartenders to turn to the Japanese...