The side of the blade is also used for smashing garlic, etc. Knife blades come in different types of steels. Carbon steel is the easiest to sharpen, however, some readers have suggested that once sharpened, stainless steel tends to stay sharp longer. To sharpen a knife, hold the blade with both hands at about a 20-degree angle over a whetstone. Sharpen the entire length of blade in a circular motion.
Whetstones are available in any asian grocery stores.