As Japanese cooking and cuisine is quite different from what we encounter in the West, so are the tools used in Japanese cooking. Traditional Japanese kitchen cutlery is still made today, primarily by hand, using the same methods, materials and designs that have been used for centuries. Yes, Japanese manufacturers make excellent versions of our Western knives and yes, Japanese manufacturers make knives in the traditional patterns but with modern and automated methods and materials. But here we are going to discuss just the traditional knives made in the hand forged traditional manner.

Materials:

Blades are made from high carbon steels called "hagane" that are quite hard after heat treating. There are several grades of hagane but the two hardest are normally used in the construction of hand forged traditional knives. The standard carbon steel is called "shiroko" or white steel and provides outstanding performance. The upgrade is called "aoko" or blue steel which is an alloy that contains some chromium and tungsten to make the steel more resistant to rust and corrosion. Aoko, however, would not be considered a stainless steel. There are actually various grades within each of these but the differences are subtle.

If one forges a knife from solid hagane and applies differential heat treatment, it is called "honyaki." This term relates to the traditional construction of the samurai sword. These knives feature differential heat treatment so that the edge is quite hard and the rest of the blade is softer. Honyaki construction provides the edge retention of hard steel and the toughness of soft steel through the differential heat treatment. It is difficult to forge and expensive. These blades come from the forge shaped like an arc and need to be straightened. This process is difficult and suffers a significant failure rate. For that reason honyaki knives are the most expensive. They are also the hardest to maintain since the steel that carries the cutting edge is thicker. But honyaki provides the best performance and feel for cooking professionals who are proficient at Japanese cuisine.

Most traditional Japanese knives are made by forge welding together a piece of hagane and a piece of soft steel or iron. This construction is called "kasumi." Kasumi means misty or foggy and the term refers to the iron which takes on a frosty appearance after heat treatment. Kasumi is easier to manufacture and less expensive for the cook to buy. It is easier to maintain because the hagane is thinner.

You can also find traditional Japanese knife patterns made from solid or kasumi stainless steel or from other grades of hagane. But the very traditional professional level knives will be hand forged using aoko or shiroko and either honyaki or kasumi construction.

Handles are traditionally made from Ho wood which is not particularly attractive but is strong and resists splitting. The front of the handle is protected with a ferrule which is made traditionally of water buffalo horn.

The wooden sheath or "saya" that accompanies most of the better traditional knives can be made of any number of materials from inexpensive hardwood to finely lacquered and decorated woods.

Patterns:

There are quite a large number of traditional patterns but the three most common are pictured here. The "yanagi" is the traditional slicer and is pictured at the top. It is used to make thin slices of fish or meat. In the West this knife is often referred to as the sushi knife or sashimi knife. It is capable of making the paper thin slices of raw fish that are common in Japanese cuisine. The "takohiki" is like the yanagi but has a flat nose instead of a point. The "fuguhiki" is a version of the yanagi with a narrower blade that is designed to be used in the preparation of the "fugu" or puffer fish.

The "usuba" is used as a slicer also but for vegetables. We often call it the vegetable knife in the West. It can make the paper thin slices of vegetables you may have encountered in a Japanese restaurant. There are basically three versions of this knife. The "azumagata" is the most popular shape and has a rectangular shape with a flat nose. It is pictured in the middle. The "kamagata" has a sheepfoot shaped blade that provides a useful point. The "hishigata" has an even more pronounced point that adds additional utility to the knife. There are also vegetable slicers made with double bevels and these are often called "nakiri."

The "deba" is the fish cleaning knife. It has a very thick and heavy blade appropriate for chopping off fish heads and tails. Some Westerners confuse the deba with the Western chef's knife but it does a poor job of doing the work of a chef knife. It makes quick work of taking a fish apart and filleting it.

Additionally there are noodle knives and tuna knives and eel knives of various shapes and forms and shellfish parers and boning knives and many other traditional patterns. Our purpose here was just to introduce you to the most popular models.

Use and care:

Traditional Japanese knives are single bevel. That means that the outside of the blade has an angled bevel to form an edge. The inside of the blade, however is flat or even concave. This is so primarily to make sharpening easier. It also makes it easy to produce acute bevel angles which are the hallmark of Japanese cutlery and appropriate for the hard steel used in their construction. It does take some time to get accustomed to using single bevel knives as they tend to want to rotate as they are used. Using them is a skill that is acquired through practice.

Most professional grade Japanese knives are made from steels that are not rust and corrosion resistant. They will discolor and very quickly. We suggest you not worry about the discoloration as it is just part of the nature of iron and carbon steel. We do suggest that you rinse them and dry them immediately after use to prevent rust.

Despite the comments to the contrary from Western cooks, Japanese knives are shipped only partially sharpened. We suggest you finish them with 1000 and 6000 grit waterstones before use. The knives may seem sharp out of the box but the application of a 6000 grit polish will make them perform as they should. Japanese chefs sharpen their traditional knives daily and we recommend you sharpen yours after the equivalent of a day's work. The 1000 and 6000 grit stones will get them back like they were at the beginning of the day.

Waterstones are used wet. They have a water soluble matrix that holds the abrasive. Start sharpening by working with the outside of the blade, the side that has the bevel. In the image you can see how the blade is tilted to the same angle at which the edge was originally cut. Holding the angle steady, make circular motions against the stone all the time moving the blade across the stone so that all of it is sharpened. After the outside is finished, then turn the blade over so that the inside contacts the stone and rests flat on it. One light swipe should clean up the inside burr on the edge and leave the blade ready to use.

Note that traditional Japanese knives perform elegantly but are more delicate than Western knives and need to be used and treated with care. Never use them for prying or undertaking jobs that should be handled with a cleaver. A little care will ensure a lifetime of good performance.

Finally, we recommend you oil the blades whenever you intend to store them for a period of time. Japanese chefs use "tubaki" or camelia oil. Another food grade oil you can use is mineral oil which is available in any pharmacy. Cooking oils will become rancid over time and should not be used.

Hopefully this brief guide will help you better understand the traditional knives we sell and help you make a more informed buying decision. Good cooking.