1 inch piece ginger, peeled and sliced into pieces (optional)
1/2 tablespoon soy sauce
1/2 tablespoon cornstarch
1/2 tablespoon oyster sauce
2 tablespoons water
1/4 teaspoon sesame oil
1/2 tsp pepper
1/2 teaspoon sugar
Marinate the chicken with the ingredients in 'marinade' for 10 minutes.
Combine all the ingredients in the 'sauce' in a small bowl, stir to blend well.
Heat 1/2 tablespoon oil in a pan or wok until the oil becomes hot. Add the chicken and quickly stir-fry until the surface of the chicken turn opaque or white. Dish out and set aside. This step seals in the juice in the chicken so the texture is tender and velvety smooth.
Heat up the remaining oil in the wok until hot. Add the ginger into the wok/pan and stir-fry until aromatic. Add the chicken back into the pan and do a few quick stirs. Add in the bok choy and stir to combine well. Transfer the sauce into the wok and continue to stir-fry until the bok choy is cooked but remain crisp.
Serve immediately as it is, with steamed rice or noodles.