Grilled Sausage and Prawn Brochettes

1/2 Japanese soy sauce

2 brown sugar

2 finely chopped garlic

2 sesame oil

2 chopped ginger

1/2 large shrimp in shells

1 medium red onion (cut into 1-inch cubes)

3 Japanese eggplants (cut into 3/4-inch rounds)

2

1/4 sweet mango chutney