Cut the chicken fillet into small pieces, add to it 2 tbsp soy sauce, 0.5 tsp rosemary, 0.3 tsp salt, 1 tsp grated ginger. Mix everything and leave it for 10 minutes.
After the time has elapsed, add 3 tablespoons of starch with a slide and leave for 1 hour.
While the chicken is marinating, prepare the sauce: mix 2 tablespoons of soy sauce, 7 tablespoons of 9% vinegar, 1 tablespoon of tomato paste and 4 tablespoons of sugar.