Source: Distillery,

This is a blend of multiple types of malt and grain that Nikka reserves. Nikka From the Barrel was created to deliver full flavors and richness of whisky "from barrels" which only blenders can sniff and taste. As the whisky contains so many characteristic components at a higher alcohol of 51.4%, it is essential to let the liquid "marriage" in used casks for 3-6 months for it to stabilize and harmonize. The concept of the unique short squared bottle is "a small lump of whisky", which perfectly visualizes the rich and strong taste of the whisky inside.