When you order a highball in Japan, it is universally implied that you are ordering a whisky highball. The drink is very personal, and this is how I prefer making them at home. In Japan, after a long day's work, people head to their local bar or izakaya and order beer and whisky highballs.
This is a great pairing with the izakaya's fried and salty snacks, which beg for a refreshing accompaniment. Moreover, at around $5 a pop, it is completely democratic and popular across all demographics. My version is the platonic ideal of simplicity and deliciousness. The trick is to keep your Japanese whisky in the freezer and your seltzer in the fridge.
The drink takes literally seconds to throw together and enjoy. It is great as an aperitif, a meal accompaniment, or just for kicking back and watching the game or a movie. Kanpai!
Technique tip: If your whisky is room temperature, stir it over the ice to bring it down in temperature. If it is coming from the freezer, as I prefer, stir it to raise the temperature and make the spirit amenable to proper dilution. Then add whatever fizzy water you have on hand, provided it is straight from the fridge.
Take a highball glass and fill it with ice. (If the glass has been stored in the freezer, you are all set. If not, simply stir the ice around to sufficiently chill the glass, then strain out any water.)2.
Gently pour a jigger's worth of whisky into the glass and stir lightly, adding more ice, if necessary.3.
Slowly and deliberately pour chilled soda water into the glass, aiming for the glass's side wall, not the ice itself, since the shock of the impact with the ice will dissipate the soda water's carbonation. Then, using a stirrer, gently lift the ice up and down a couple of times to mix the whisky and soda water, and give it a slow, gentle stir.4.
A citrus twist garnish is optional, with lemons, limes, yuzu or other citrus fruits all popular.