Place the pork in a bowl with the wine or sherry and 2 tspn of the soy sauce.
Mix well, then leave to marinate for 20 minutes or so.
Heat the oil in a wok or frying pan over moderate heat.
Add the garlic and fry until golden brown to flavour the oil.
Remove the garlic with a slotted spoon and discard.
Add the pork to the wok and stir-fry until it changes colour.
Add the bamboo shoot, the remaining soy sauce and the vinegar.
Stir-fry for 30 seconds.
Add the spring onion and continue to cook for 30 seconds more.