Rinse and soak mushrooms to rehydrate. When mushrooms are soft, wash to remove any grit. Trim stalks and soak again until ready to be used.
In a medium sized pot, heat vegetable and sesame oil. Fry ginger and garlic until fragrant, about 1 to 2 minutes. Add chicken pieces and fry until opaque. Stir in dark soy sauce.
Remove mushrooms from soaking liquid and reserve ½ cup (120ml) of the liquid. Add mushrooms and soaking liquid to the chicken. When sauce comes to a boil, add Shao Hsing cooking wine , sugar, and salt. Reduce heat to low and allow it to simmer for 45 minutes, stirring occasionally.
Mix cornstarch with 2 tablespoon of water in a small bowl. Pour over chicken and let it continue to cook for another 5 minutes. Sauce should have thickened.