Remove skin from swordfish if intact. Cut the fish into bite size pieces, about 2-3cm (1") cubes and put them in a bowl or a zip lock bag.
Heat oil in a non-stick fry pan set over medium heat, and place the fish pieces in the pan. Cook for 1-2 minutes or until golden brown, then turn. Keep turning like this ensuring that all sides of the cube are cooked and golden brown.
Transfer the fish from the pan to the sauce bowl/plate and mix so the fish is coated with the sauce. Marinate for about 15 min.
1. You can substitute rice wine vinegar to white wine vinegar.
2. It can be served at room temperature and is good the next day too in bento (弁当, lunch box).