You can get your fish monger to do this for you, and lay them all out nicely on ice for you, but it will be at a premium price. And you’d be missing out. Part of the joy in eating a delicious, sexy, luxurious oyster is the effort — and the skill — it takes to open one. The key is to securely wrap the oyster with a towel (or alternately a fancy oyster glove, if you’re into accessories), locate the hinge with the tip of your knife and work your way in between the bottom and top shells with the tip. Once you’ve got a little leverage (you’ll know when you do), push forward with the knife to separate the two shells slightly, then slide the knife along the minuscule slit across the side of the oyster while twisting the knife ever so slightly, and the two shells will pry open. Once you’re in, use the knife to detach the oyster from the top shell and then do the same to release it from the bottom shell. Mind the liquid — you don’t want to lose that precious liquor. It’s the briny sauce that comes with the oyster. Flip the oyster to the smooth “presentation side” and serve on ice with the mignonette, or lemon, or hot sauce, or however you enjoy them.