Combine the soy sauce, brown sugar, mirin, ginger, and garlic in a small saucepan.
Bring to a boil then simmer for 10 minutes. Simmer longer if a thicker sauce is desired.
Serve immediately over grilled or baked chicken.
Or remove from heat and set aside to cool slightly before storing.
Video
Notes
This sauce can be refrigerated for up to 5 days stored in an airtight container.It can also be frozen for up to 2 months. Cool the sauce completely then transfer to a freezer-safe container. When ready to use, thaw in the refrigerator overnight and use immediately.