Mirin is a sweet rice wine used in Japanese cuisine.
Most Japanese dishes use sugar, but they are used just enough not to taste it in the food. The main purpose of sugar is to bind the flavors of the other seasonings and condiments, and not to give it a sweet taste.
Mirin is a type of rice wine similar to sake, but with a lower alcohol content and higher sugar content. The sugar content is a complex carbohydrate that forms naturally during the fermentation process; no sugars are added. The alcohol content is further lowered when the liquid is heated.
It is used instead of sugar to prevent the food from tasting too sweet.
Mirin is used for this purpose, since it is not sweet as pure sugar, and also has a nice aroma. It is like a light syrup, and it should be used in small amounts.