Combine the oyster sauce, chicken stock, Shao Hsing wine, sugar and sesame oil in a small saucepan. Bring to a boil and cook until sauce thickens. Set aside.
Wash the gai lan in cold water. Trim off and discard the tough bottoms. Peel stalks if they are thick and tough; leave gai lan whole or cut into thirds.
Bring 3 to 4 litre of water to a boil in a wok or stock pot; add the salt and oil. Add the greens, bring back to a second boil. Turn off the heat and let greens stand for a minute or two. When the green stalks brighten, test one for doneness. It should be tender and crisp. Drain immediately and shake off excess water.
Transfer to a platter, pour dressing over, and serve immediately.
Serves 4 to 6.
Notes: Gai lan is Chinese broccoli. It's not much like the Western stuff. It has thinner stems, flowers and leaves and is eaten more as a green.