Japanese whisky is modelled after the Scotch tradition—double distilling malted and/or peated barley—before it's aged in wood barrels. As opposed to the sweeter American bourbons and ryes, which tend to be drier, smokier, and peatier, and come as single malts or blends.
How the Japanese Drink Their Whisky
The typical Japanese way of drinking whisky, mizuwari literally means "mixed with water." It's served during the meal in a glass filled with ice. The whisky is transformed into a less alcoholic drink while retaining most of its flavour. This is the most common way to drink whisky in Japan, especially in Japanese gourmet restaurants.
For a perfect mizuwari, fill your glass with ice and add one dose of whisky for 2 to 2.5 doses of mineral water. The highball is the sparkling version of mizuwari where whisky is mixed with sparkling water. Drink your favourite Japanese whisky as a mizuwari and you will discover it in a new light.
Excerpt from How Would You Like Your Japanese Whisky?