The santoku bōchō ( 三徳包丁?) or bunka bōchō ( 文化包丁?) is a general-purpose kitchen knife originating in Japan. Its unbolstered blade, which is typically between five and eight inches long, has a flat edge and a sheepsfoot blade that curves in an angle approaching 60 degrees at the point. The top of the santoku's handle is in line with the top of the blade, giving the chef's fingers plenty of room underneath. The word santoku loosely

translates as 'three virtues' or 'three uses', a reference to the three cutting tasks the knife performs so well: slicing, dicing, and mincing. The santoku's blade and handle are carefully designed to work in harmony by matc hing the blade's width/weight to the weight of blade tang and handle, and the original Japanese santoku is an especially well-balanced knife.

The santoku was originally designed as a modification of the western (especially French) beef or chef's knife, adapted to prepare Japanese cuisine. Shorter than most chef's knives, the blade's cutting edge is normally hardened above the latter and is optimized for cutting fish, vegetables, and smaller-boned and/or boneless meats, using traditional Japanese edge geometry.

In comparison to most western chef's knives, the original Japanese santoku pattern has a thinner flat-ground blade made of harder tempered steel ( often 58–62 HRC or higher). This blade design in turn allows a more acute angle on the cutting edge (edge profile) that makes the knife ideal for precision cutting and thin

slicing. While a typical western chef's knife might have an edge profile angle of 20–22 degrees, a santoku normally has an angle of 15–18 degrees. The santoku's sharp, tough cutting blade makes the knife ideal for most ordinary kitchen cutting chores. However, because of its shorter blade and hardened, thin-profile edge, the santoku is not designed for cutting against thick bones, kitchen sinks, or other hard surfaces, which could damage or chip the cutting edge. The santoku is especially popular among people with smaller hands, and modified santoku-type knives (made outside of Japan) have appeared on television in the hands of female chefs such as Giada de Laurentiis.

Other Japanese modifications of the basic santoku pattern include piercings through the body of the blade, hand-hammered blades (which are said to improve strength while presenting a more rustic appearance), and kuro-uchi, a process that leaves the rough black finish from the forge on most of the blade. Some of the best blades employ San Mai laminated steels, including the pattern known as suminagashi ( 墨流し literally, "floating-ink paper"). The term refers to the similarity of the pattern formed by the blade's damascened and multi-layer steel alloys to the traditional Japanese art of suminagashi marbled paper. Forged laminated stainless steel cladding is employed on better Japanese santoku knives to improve strength and rust resistance while maintaining a hard edge. Knives possessing these expensive laminated blades are generally considered to be the ultimate expression of quality in a genuine Japanese santoku.

Many copies of santoku-pattern knives made outside Japan have substantially different edge designs, different balance, and softer steels (thus requiring a thicker cutting edge profile) than the original Japanese santoku. One trend in some non-Japanese santoku variations made of a single alloy is to include kullenschliff, scallops or recesses (known as kullens) hollowed-out of the side of blade similar to those found in meat-carving knives. These scallops create small air pockets between the blade and the material being sliced in an attempt to improve separation and reduce cutting friction. However, manufacturing limitations generally limit such features to mass-produced blades fabricated of softer, less expensive stainless steel alloys. Genuine Japanese santoku blades do not use such features but instead rely on inherent quality of steel and edge geometry to make clean cuts.