A whisky highball with seltzer or club soda is one of the most popular items on Japanese drink menus. It’s a lovely way to enjoy a good Japanese whisky; the effervescence of the sparkling water softens the alcohol and allows the aromatics to be fully enjoyed.
Add the Japanese whiskey to a tall ice-filled glass. Top with sparkling water to fill the glass, and stir the drink gently with a barspoon to build up a bit of froth. Add a lemon twist or wedge, or leave ungarnished.