For this dish, thin slices of beef are grilled quickly resulting in tender, flavorful strips of meat. The Korean market sells the meat already cut into thin slices. Otherwise, my local butcher said that if I call in advance, he will slice the meat for me by freezing a whole piece of raw meat for about a half hour, and then will slice it thinly in the commercial slicer. This freezing tip can be used at home as well. Be sure to cut the meat against the grain so the meat will be tender.