1/2 cup ketchup
2 tablespoons soy sauce
1 tablespoon brown sugar
1 tablespoon mirin (Japanese sweet wine)
1 1/2 teaspoons Worcestershire sauce
1 teaspoon grated fresh ginger
1 clove garlic, minced

Stir ketchup, soy sauce, brown sugar, mirin, Worcestershire sauce, ginger, and garlic together in a bowl.
Let flavors blend for at least 1/2 hour.