Mirin

is a common ingredient (or stuff) in Japanese cooking.
The term "Mirin" is a general name that resembles a close taste for cooking purpose. But there are two types. One is a traditional type called "本みりん", which was developed a hundred years ago. It is produced almost all from rice, kōji and alcohol. During brewing process, about 14 % of alcohol is included, so that it protects mirin from going bad or spoiling. In fact sugar is not added to it. Mirin is a kind of rice wine similar to sake. Sweetness comes from its brewing process. 
The other is a fake of 本みりん, often called "みりん風調味料", which hardly contains alcohol and adds sugar and broth instead. It is 40%–50% sugar. Thus, new type is usually sold much cheaper in market. This kind of Mirin contain less alcohol. 
In Kansai style cooking, mirin is boiled for a short time. This removes some of the alcohol. Kansai-style boiled mirin is called "nikiri mirin" (煮切り味醂).But usually it is boiled enough to take alcohl away in cooking.
Mirin is used in teriyaki sauce, too.Mirin is popular and widely used for Japanese dishes.