Rice wine
From Cookipedia
An essential ingredient in Chinese cooking. Rice wine is made by fermenting freshly steamed glutinous rice with yeast and water. It's relatively low in alcohol. It's culinary use is mainly in sauces and marinades. It is widely available in Asian markets, often labeled as Shaoxing wine.
It's often confused with saké and mirin but saké (a Japanese rice-based brewed alcohol) is far more delicate in taste. Mirin is sweetened saké, made for cooking.
Substitute a dry pale sherry for rice wine if you can't obtain it.