Santoku

The santoku bōchō or bunka bōchō  is a general-purpose kitchen knife originating in Japan. Its blade is typically between 13 and 20 cm long, and has a flat edge and a sheepsfoot blade that curves down an angle approaching 60 degrees at the point. The term santoku may refer to the wide variety of ingredients that the knife can handle: fish, meat, and vegetables, or to the tasks it can perform: chopping, dicing, and slicing, with either interpretation indicating a multi-use, general-purpose kitchen knife. The blade and handle of the santoku are designed to work in harmony by matching the blade's width and weight to the weight of the tang and the handle.

History
The santoku knife design originated in Japan, where traditionally a gyuto knife is used to cut meat, a nakiri knife is used to cut vegetables and a deba knife is used to cut fish. The santoku knife was created in the 1940s.

Design
Santoku blade geometry incorporates the sheep's foot tip. A sheep's foot design essentially draws the spine ('backstrap') down to the front, with very little clearance above the horizontal cutting plane when the blade is resting naturally from heel to forward cutting edge. Providing a more linear cutting edge, the santoku has limited 'rocking' travel (in comparison to a German/Western-style chef's knife). The santoku may be used in a rocking motion; however, very little cutting edge makes contact with the surface due to the extreme radius of the tip and very little 'tip travel' occurs due to the short cantilever span from contact landing to tip. An example of this limitation can be demonstrated in dicing an onion—a Western knife generally slices downward and then rocks the tip forward to complete a cut; the santoku relies more on a single downward cut and even landing from heel to tip, thus using less of a rocking motion than Western style cutlery.

The santoku design is shorter, thinner, and so lighter, with more hardened steel in the tradition of Samurai sword steel (to compensate for thinness) than a traditional European chef's knife. Standard santoku blade length is between 6 and 7 in, in comparison to the typical 8 in European cook's knife. Most classic kitchen knives maintain a blade angle between 40 and 45 degrees (a bilateral 20 to 22.5 degree shoulder, from cutting edge).

Japanese knives typically incorporate a kataba chisel-edge (sharpened on one side), and maintain a more extreme angle (10 to 15 degree shoulder). A classic santoku, rather, incorporates the European-style, bilateral cutting edge, but maintain a more extreme 12 to 15 degree shoulder, akin to Japanese cutlery. It is critical to increase the hardness of santoku steel so edge retention is maintained and 'rolling' of the thin cutting edge is mitigated. However, harder, thinner steel is more likely to chip, when pushing against a bone for example. German knives use slightly 'softer' steel, but have more material behind their cutting edge. For the average user, a German-style knife is easier to sharpen, but a santoku knife, if used as designed, will hold its edge longer. With few exceptions, santoku knives typically have no bolster, sometimes incorporate 'fluted' sides, also known as a Granton edge, and maintain a more uniform thickness from spine to blade.

Variations
Some of the knives employ san mai (or 'three layered') laminated steels, including the pattern known as suminagashi (墨流し). 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 higher quality Japanese santoku knives to improve strength and rust resistance while maintaining a hard edge. Knives possessing these laminated blades are generally much more expensive to match the higher quality.

There are many copies of santoku-pattern knives made outside Japan that have substantially different edge designs, different balance, and different steels from the original Japanese santoku. One trend in santoku copies made of a single alloy is to include fluting or recesses, hollowed out of the side of the blade, similar to those found in meat-carving knives. This fluting creates small air pockets between the blade and the material being sliced in an attempt to improve separation and reduce cutting friction.