In a bowl, combine cornstarch, sherry, salt and pepper. Add chicken and stir to coat, then stir in 1.5 t of the oil and let stand for 15 minutes to marinate. Prepare cooking sauce by blending all ingredients in another bowl, set aside. Place a wok or wide frying pan over high heat. When pan is hot, add 2 T of the oil. When oil begins to heat, add garlic, ginger, and black beans. Stir once, then add chicken and stir-fry until chicken is opaque (about 3 minutes). Remove chicken from pan. Add the remaining 1 T oil to pan. When oil is hot, add green pepper, carrot and bamboo shoots. Stir-fry for 30 seconds. Add water and stir-fry for 1.5 minutes. Return chicken to pan. Stir cooking sauce, add to pan, and cook, stirring, until sauce bubbles and thickens. If you like food that produces watery eyes and a burning mouth, pass a little bowl of hot pepper & black bean sauce (recipe follows).