In 2014 Japan's most popular distillery, the Yamazaki, released the first expression in its Limited Edition series, and has since released a new one each year . This release marks the fourth release and are the last in this limited edition range, which grows more popular every year. A single malt comprising of vintages of up to 20 years old, including whiskies matured in bourbon, sherry, and European oak casks. Suntory is quite secretive concerning the production of these expressions.