Heat 2 tablespoons of oil in a frying pan or wok, add the beef and stir fry for a few minutes.
Add the rice wine, salt, soy sauce, ginger, spring onion and enough water to cover the beef. Cover the pan and simmer until the beef is cooked through.
Add the potatoes and a little more water if necessary (beef and potatoes should be immersed in liquid) and cover the pan again. Simmer until the potatoes are soft and the beef is very tender. Transfer to a serving bowl.