Stir together the soy sauce, brown sugar, catsup, water, garlic, onion, ginger, black pepper, oregano, red pepper flakes, and paprika in a large glass or ceramic bowl. Mix well until sugar is dissolved.
Add the chicken and toss to evenly coat. Cover the bowl and marinate the chicken (in the refrigerator) for at least 1 hour. When ready to cook remove chicken from marinade and throw away the marinade.