The main ingredients of sake are rice, rice koji, and water. Sake brewers design the ingredients and production process with the finished sake in mind. Even with the same ingredients and production process, the aroma and taste of sake can vary depending on where and by whom the sake is made. The "SAKE BOOK (not for sale)" included in the package is a text book that will help you find the sake you like. It is so different...we believe you will have such an impression.