Ironically, it's a little unlikely that Yamazaki barrels are charred. American whiskey is aged in new oak, which is charred or toasted both to standardize quality and also to bring out caramel and vanilla notes from the wood. But single malt scotch is generally aged in used barrels and the barrels are selected in part for the characteristics of what was aged in them before, which is why the "best whiskey in the world" Yamazaki 18 Sherry Cask costs so much. Charring is what you do, in Scotland, to an exhausted cask; it's also something Scotch distillers work to mitigate in ex-bourbon casks.