A cleaver is a large knife that varies in its shape but usually resembles a rectangular-bladed hatchet. It is largely used as a kitchen or butcher knife intended for hacking through bone. The knife's broad side can also be used for crushing in food preparation (such as garlic).
In contrast to other kitchen knives, the cleaver has an especially tough edge meant to withstand repeated blows directly into thick meat and dense cartilage and even bone, not to mention the cutting board or other supporting surface below. This resilience is accomplished by using a softer steel and a thicker blade, because a harder steel and a thinner blade will fracture more readily. Formerly, weaker knives would suffer buckling failure when used in a cleaving fashion.
In contrast to all other kitchen tools but one, a meat tenderizer, it is the only one designed to be swung like a hammer.
The edge of a meat cleaver does not need to be particularly sharp, because the knife's design, like that of a hatchet or an axe, relies on sheer momentum to cut efficiently, to chop straight through rather than slicing in a sawing motion. Part of the momentum derives from how hard the user swings the cleaver, of course, and the other part derives from how heavy the cleaver is.
A knife-sharp edge on a cleaver is undesirable because it would quickly become more blunt than it would if it were less sharp but sturdier to begin with. The grind of Eastern Asian kitchen knives is 15–18 degrees, and for most Western kitchen knives it is 20–22°; but for a meat cleaver it is even blunter, approximately 25°.
The tough metal and thick blade of a cleaver also make it a suitable tool for crushing with the side of the blade. This contrasts with certain hard, thin slicing knives, which should not be used for crushing because they can crack under such repeated stress.
Cleavers are primarily used for cutting through thin or soft bones and sinew. With a chicken, for example, it can be used to chop through the bird's thin bones or to separate ribs. Cleavers can also be used in preparation of hard vegetables and other foods, such as squash, where a thin slicing blade runs the risk of shattering.
Cleavers are not used for cutting through solid, thick and hard bones – instead a bone saw, either manual or powered, is used.
Cleavers occur with some frequency in traditional Chinese thought.
An old Daoist story on the proper use of a cleaver tells of a butcher who effortlessly cut ox carcasses apart, without ever needing to sharpen his cleaver. When asked how he did so, he replied that he did not cut through the bones, but rather in the space between the bones.
The Chinese chef's knife is frequently incorrectly referred to as a Chinese "cleaver" due to the similar rectangular shape. Although the Chinese chef's knife looks much like the cleavers familiar in butcher shops in Europe and North America, Chinese chef knives are much thinner in cross-section and are intended more as general-purpose kitchen knives, as a chef's knife. A Chinese chef's knife is mostly used to slice boneless meats, chop, slice, dice, or mince vegetables, and to flatten garlic bulbs or ginger, while also serving as a spatula to carry prepared ingredients to the wok.
For butchering tasks and to prepare boned meats, the Chinese have long produced a heavier series of 'bone' cleavers designed to take care of tasks similar to the Western meat cleaver.