Japanese chef knives were developed mainly for slicing or chopping raw fish and vegetables, and have unique designs that make them particularly efficient for these tasks. Unlike European knives, they are often single ground blades (kataba), where only one side of the blade is angled. This makes it possible to produce very thin, precise slices, but requires more skill to use. Single ground blades come in the standard right-handed version. Left-handed knives are rare and generally custom made. 18 to 30 degree sharpening angles are typical, much like European blades, although for similar uses, Japanese blades tend to be honed to a more acute angle. Sushi knives are sharpened as acutely as 10 degrees, less than most razor blades. This sharpening process is very demanding, requires the highest quality steel, and the delicate edge requires extreme care to prevent nicks, chips, and blade rolling. Ryoba, or double ground blades are also made, mostly for home kitchens and easy to maintain and steel will hold a sharp edge, resist rust and be easy reshape.
Kasumi and Honyaki There are basically two grades of traditional Japanese chef knives. Kasumi blades, especially the laminated Damascus ones, are superior to single forged honyaki blades, which are usually considered better than blades produced by stamping. Better knives have full tangs, stronger assembly techniques, better balance, and in particular, higher quality steel. At the high end, custom knife smiths achieve fame for their artistry and craftsmanship.
Creating Honyaki is long and arduous process Due to its characteristically sharp hard edges the blade retain its sharpness for a long time,by the same token, these these knives take longer to sharpen, and in general, are more difficult to upkeep. Honyaki is preferred by most skilled professional chefs.
In contrast, Kasumi is easier to maintain. The blades on a Kasumi consist of two layers of metal forged together. The flat backside of the knife is made of hand durable. The front polished side is a softer steel, which simplifies the sharpening process. Although easier to care for Kasumi tend to dull more quickly.
Parts of Japanese Knives
It may be useful to know the parts of Japanese knives and their names. The illustration below shows the essential parts of a traditional Japanese knife.
- Tip (切っ先 / KISSAKI).
- Blade Path (切り刃 / KIRIBA), the inclined surface of the entire blade starting from shinogi to edge.
- Shinogi (しのぎ / SHINOGI), the ridge line.
- Spine (みね / MINE), the top part of the blade.
- Edge (刃先 / HASAKI), the entire cutting edge of the knife.
- Heel (あご / AGO）.
- Machi (マチ / MACHI), is the notched neck portion.
- Bolster (桂 / KATSURA), also known as ferrule.
- Handle (柄 / E).
- Butt (柄尻 / EJIRI), the end of the handle.
- The yanagi, usuba, and gyuto are measured from the machi (macho) to the tip of the blade.
- The deba and mioroshi are measured from the heel (ago) to the tip of the blade.