225 g (8 oz) lean beefsteak, cut into thin strips
1/2 tsp salt
4 tbsps vegetable oil
1 red and 1 green chilli, cut in half, seeded and sliced into strips
1 tsp vinegar
1 stick celery, cut into thin 5 cm (2 inch) strips
2 carrots, cut into thin 5 cm (2 inch) strips
1 leek, white part only, sliced into thin 5 cm (2 inch) strips
2 cloves garlic, finely chopped
1 tsp light soy sauce
1 tsp dark soy sauce
2 tsps Chinese wine, or dry sherry
1 tsp caster sugar
1/2 tsp freshly ground black pepper