Classifications of premium sake are referred to as tokutei meishoshu. This is a provision under Japanese trade law created in 1992. In order to qualify for this provision, the amount of rice koji must be more than 15% of the total weight of rice used, the additional alcohol (if any) used should be less than 10% of total weight of rice used, and rice has to be certified and graded. There are 8 types of sake in tokutei meishoshu, which are classified depending on seimaibuai, or rice polishing ratio, and the combination of raw ingredients.