Combine soy sauce, peppercorns, garlic, and bay leaves in a large bowl. Stir.

Add the sliced chicken piece by piece. Make sure that the chicken gets coated with soy sauce. Cover the bowl and refrigerate for 3 hours to marinate the chicken.

Heat oil in a pot.

Put the chicken pieces gently into the pot. Cook each side for 2 minutes.

Pour the remaining marinade into the pot. Add chicken broth (or water). Let boil. Cover the pot and cook in low heat for 40 minutes.

Pour the vinegar in the pot. Let the liquid re-boil. Stir.

Add the sugar. Continue to cook until the sauce reduces to your desired consistency.

Serve with warm white rice.