Also easy to make your own! Just combine 1/4 cup ordinary soy sauce (I use Kikkoman) and 1/4 cup brown sugar over medium heat. Bring to a simmer and reduce until it becomes a maple syrup consistency. It will thicken more when it cools.
2. Chilli – I use 2 birds eye or Thai red chillies, adds a mild warmth, doesn’t make it spicy. Adjust to taste. Chilli paste can also be used instead – add it when you add the rice.