Marbling is the visible flecks and streaks of intramuscular fat running through a cut of meat, most discussed in beef. It's a key indicator of quality: as the fat melts during cooking, it bastes the muscle from within, making the meat more tender, juicy, and flavorful. USDA grades beef largely on marbling, from Select (least) up through Choice to Prime (most); Wagyu, a Japanese cattle breed prized for exceptional marbling, and Kobe beef, one certified regional variety of Wagyu, run well beyond the USDA scale. Well-marbled cuts suit dry-heat methods like grilling, pan-searing, and roasting, since the internal fat helps keep them moist, while leaner, less-marbled cuts generally do better with moist, slow methods like braising.