1. Meanwhile, cut the chicken into 1 inch cubes. Put them in a bowl together with the sherry or rice wine and the soy sauce (1) and let the mixture stand 10 minutes or so. Dice mushrooms into thin strips. Finely shred the ham or dice bacon. Bring the stock to a simmer in a large pot. Drain the marinade (but not the chicken cubes) into the stock. Add the mushrooms, finely chopped spring onions, ham or bacon and remaining soy sauce
2. Continue to simmer the soup and meanwhile heat the oil in a wok or large frying pan. When really hot, stir fry the chicken over high heat until they are nicely brown - this should take about 5 minutes. Drain them on a paper towel and then add them to the soup. Simmer together for 5 minutes and the soup is ready to serve.