Sake is a clear alcohol drink brewed from rice. Sake generally contain about 15-16% alcohol. It's said that good water and rice make good sake.
Sake can be divided into two kinds: futsu-shu (general sake) and tokutei meisho-shu (special sake). Futsu-sho are cheaper than tokutei meisho-shu. According to the National Tax Agency Japan, tokutei meisho-shu are categorized into 8 types, depending on the ingredients, the method of sake brewing, and more. Main types of tokutei meisho-shu are honjozo-shu, junmai-shu, and ginjo-shu.
In general, namazake (sake which has not been pasteurized) and ginjo-shu are chilled for drinking, and regular sake, honjozo-shu, and junmai-shu are warmed for drinking.
Buy a sake with recent bottling date. Sake is sensitive to the sunlight and the heat. It's best to store sake in the refrigerator or in a dark and cool place. Namazake must be stored in the refrigerator. Once a sake bottle is opened, keep it in the refrigerator.
Sake is often used in Japanese cooking. Leftover sake can be used for cooking.