Ketjap manis is used in Indonesian cooking. It can be hard to find, although these days can be ordered online--or you can make your own.
2 cups dark brown sugar
2 cups water
1 1/2 cups soy sauce
3/4 cups molasses
1/2 tsp ground laos or ginger
1/2 tsp ground coriander
1/2 tsp freshly ground black pepper
Combine the sugar and water in a large heavy saucepan and bring to a boil over moderate heat, stirring until the sugar dissolves. Turn heat up to high and cook briskly, uncovered, for 5 minutes, or until the syrup reaches 200F on a candy thermometer. Reduce heat to low, stir in remaining ingredients, and simmer for three minutes. Strain the sauce through a sieve. The ketjap will keep at room temperature for 2-3 months if tightly covered, although I prefer to refrigerate it. Yields approximately 1 quart.