Cover the palm of your hand with a folded tea towel. Place the cupped side of the oyster into your hand, with the flat side facing up.
Holding the oyster firmly with the towel insert the oyster knife into the hinge and lever upwards with a twisting motion.
Slide the blade along the underside of the shell to sever the muscle inside.
Use the knife to flip open the top shell, and then sever the muscle underneath which attaches the base of the oyster to the bottom shell.