Mix well all the Japanese marinade ingredients in a small bowl.
Marinate the sea bass in the mix for at least 1 hour. (it get’s better if you can keep it overnight in an air-tight container).
Place a pan over medium heat, and when it’s hot, add the butter and pan fry the asparagus for about 5 minutes. Sprinkle with salt and set aside on a plate.
In the same hot pan, add the fish fillets skin down first. They will need about 2-3 minutes on each side to get cooked through and form a caramelised crust on the top.
Place the asparagus on a plate, put the sea bass on top and sprinkle with fresh sliced chilli and watercress.