(diluted with 4-6 tbsp water, for marinade)
Mix diluted oyster sauce, rice wine, brown sugar and soy sauce in wok/skillet and heat on low to ensure the sugar dissolves.
Add chicken wings in the wok/pan and space them well. Technique: Use a spoon to continuously spoon/drizzle the oyster sauce mix contained in the pan, over the chicken wings while simmering in oyster sauce mix in the pan. This will ensure the chicken wings are uniform in golden brown appearance.
Then allow the chicken wings to simmer low heat (pan covered) for a while till the sauce reduce further. There will be no gravy/sauce for this dish as intended to be.
Note: You could also start by deep frying the chicken wings before covering it in the oyster sauce marinade. This would allow the wings to be more crisp.