Japanese Knives

There are many of different types of Japanese kitchen knives. The most commonly used are the deba bocho (kitchen cleaver), the santoku hocho (all-purpose utility knife), the nakiri bocho and usuba hocho (Japanese vegetable knives), and the tako hiki and yanagi ba (sashimi slicers).

Categories of Japanese Kitchen Knives
There are two categories of traditional Japanese knives - Honyaki and Kasumi. The method and material used in forging the knife determines its category. Honyaki are forged knives made entirely of one material, high-carbon steel. Kasumi knives are made from two materials. High-carbon steel and soft iron are forged together (like traditional samurai swords) resulting in San Mai blades where the steel forms the blade's edge and the iron forms the blade's body and spine. Based on their kirenaga (duration of sharpness) and hardness, however they are more difficult to use and maintain. There are two additional types of Kasumi knives.Hongasumi are forged from very high grade steel whilst Damascus knives use multilayered steel to improve their kirenaga (duration of hardness).

Japanese Knife Design and Philosophy
Unlike Western knives, Japanese knives are often single ground, i.e. sharpened in such a way that only one side holds the cutting edge. It was originally believed that a blade angled only on one side makes better and cleaner cuts, although requiring more skill in its use than a blade with a double-beveled edge. Usually, the right hand side of the blade is angled, as most people use the knife with their right hand, with angles ranging from 30deg for the average chef's knife, to 10 deg for professional sushi chef knives. Since the end of World War II, Western style double-beveled edged knives have become much more popular in Japan, the best example being that of the Santoku, a Japanese adaptation of the gyuto, the French chef's knife. While these knives are usually honed and sharpened on both sides, their blades are still given Japanese-style acute-angle cutting edges along with a very hard temper to increase cutting ability. Professional Japanese cooks usually own their personal set of knives, which are not used by other cooks. Some cooks own two sets of knives, which they use on alternate days. After sharpening a carbon-steel knife in the evening after use, the user normally lets the knife 'rest' for a day to restore its patina and remove any metallic odour or taste that might otherwise be passed on to the food.

Types of Japanese knives

Santoku Knife - Used for Fish, meat and vegetables
The santoku boch or bunka boch is a general-purpose kitchen knife originating in Japan. Its unshouldered blade, which is typically between five and eight inches long, has a flat edge and a sheepsfoot blade which 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 good things' or 'three uses', a reference to the knife's three cutting tasks it performs so well: slicing, dicing, and mincing. The santoku's blade and handle are carefully designed to work in harmony by matching the blade's width/weight to the weight of blade tang and handle. The santoku was originally designed as a modification of the Western (especially French) beef or chef's knife, adapted for use in preparing Japanese cuisine. Shorter than most chef's knives, the blade's cutting edge is normally harder and is designed for cutting fish, vegetables, and smaller-boned 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 thick bones and hard surfaces, which can 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.

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 which 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 ('floating ink mist'). Suminagashi refers to the blade's damascened and multi-layer steel alloys that resemble the traditional Japanese art of suminagashi, floating swirls of ink over paper. Forged laminated stainless steel cladding is also 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. It is important to note that 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 those used in 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. Genuine Japanese santoku blades do not employ such features, but instead rely on inherent quality of steel and edge geometry in order to make clean cuts.

Deba bocho - for cutting fish
Deba bocho (pointed carving knife) are Japanese style kitchen carvers used to cut fish, but also chicken and meat. There are different sizes up to a length of 30 cm (12 inches). The deba is not intended to chop large diameter bones.

Nakiri and Usuba bocho - vegetable knives
The professional vegetable knife Nakiri bocho (knife for cutting greens) and usuba bocho (thin knife) are Japanese-style vegetable knives. They differ from the deba bocho in their shape, as they have a straight blade edge suitable for cutting all the way to the cutting board without the need for a horizontal pull or push. These knives are also much thinner. While the deba bocho has a heavy blade for cutting through thin bones, the blade is too thick for chopping vegetables and can break the vegetable slice due to the thickness of the blade. The nakiri bocho and the usuba bocho have a much thinner blade suitable for cutting vegetables. Nakiri bocho are knives for home use and usually have a black blade. The shape of the nakiri bocho differs according to the region of origin, with knives in the Tokyo area being rectangular in shape, whereas the knives in the Osaka area have a rounded corner.The cutting edge is angled from both sides, called ryoba in Japanese. This makes it easier to cut straight slices. Usuba bocho are vegetable knives used by professionals. They differ from the Nakiri bocho in the shape of the cutting edge. While the nakiri bocho is sharpened from both sides, the usuba bocho is sharpened only from one side, a style known as kataba in Japanese. The highest quality kataba blades even have a slight depression on the flat side. This kataba style edge gives better cuts and allows for the cutting of thinner slices than the ryoba used for nakiri bocho, but requires more skill to use. The sharpened side is usually the right side for a right hand use of the knife, but knives sharpened on the left side are also available for left hand use. The usuba bocho is also slightly heavier than a nakiri bocho, although still much lighter than a deba bocho.

Sashimi hocho - raw fish knife
The Tako hiki (octopus-puller), yanagi ba (willow blade), and fugu hiki (pufferfish-puller) are long thin knives used in the Japanese kitchen to prepare sashimi, (sliced raw fish) and seafood. They are all types of sashimi bocho. Similar to the nakiri bocho, the style differs slightly between Tokyo and Osaka. In Osaka, the yanagi ba has a pointed end, whereas in Tokyo the tako hiki has a rectangular end. The tako hiki is usually used to prepare octopus. A fugu hiki is similar to the yanagi ba, except that the blade is thinner and more flexible. As the name indicates, the fugu hiki is traditionally used to slice very thin fugu sashimi.

Unagisaki hocho - Japanese eel knife
A Unagisaki hocho is a knife specialized for filleting eel. The sharp tip is pushed into the eel near the head, and then slid along the body of the eel to open up the entire length of the fish. Besides the standard there are also local styles that differ significantly for Nagoya, Osaka, and Kyoto.

Udon kiri - Knife to make udon
A udon kiri or soba kiri is a specialized knife used in the Japanese kitchen to make soba and udon noodles. The knife is also sometimes called menkiri bocho, menkiri bocho. To make soba or udon the dough is flattened and folded, and then cut with the menkiri bocho to produce long rectangular noodles. For this purpose the menkiri bocho has a straight and long cutting edge to cut the noodles straight to the board. The knife is usually heavy to aid in the cutting of the noodles, usually with a slight forward motion.