Sake is for drinking and for cooking and is one of the key Japanese flavorings, along with soy sauce, mirin, dashi, and sugar. For cooking purposes, any inexpensive brand will do. It can even do for drinking, warmed in your microwave for about a minute. As with fine wines, there is a whole world of fine sake that I am not going to get into here. Just know that for cooking, the most basic sake will be fine, so buy the big bottle—it’s inexpensive and keeps well in the pantry (no refrigeration necessary).