The 'Single' in Single Grain here refers to the fact that this whisky was made at one distillery. The distillery in question is none other than Fuji, located on the foothills of the famous volcano.
Made primarily with corn, finished whisky is a composite of three styles of distillation - American Bourbon, Scotch & Canadian. Fuji leans into the heavier, bolder Bourbon flavors but with the Japanese touch for blending that renders it more subtle and really well integrated and easy to sip.
In the best sense it is like a Japanese Bourbon, which makes sense as the parent company here, Kirin, has plenty of experience with Bourbon, being the longtime owners of Four Roses.