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Japanese Knife Glossary & Kanji

Akatsuchidoro – a special red mud clay primarily used in Japan for construction but used in the traditional Japanese bladesmith shop for thinly coating blades before quenching.

Baikin – the Japanese word for germs.

Gokunantetsu – mild steel used primarily as a toughening outer laminate on Japanese laminated blades.

Hineribo – a bar or stick with a slot cut into it to torque twisted blades straight.

Kata-ha – literally “one edge,” a two-layer laminate usually consisting of a hard carbon steel layer and a soft gokunantetsu layer.

Kobuse – a style of blade construction, primarily found in modern samurai sword blades, consisting of a mild steel core with a hard carbon steel wrap around the outside.

Magebo – a bar or stick with slots cut into it to straighten a bent blade.

Shinogi – the ridge line separating the secondary edge on a blade from the blade flats.

Tagane – a hammer with very hard carbide bits used to straighten bent or twisted blades by displacing small amounts of steel. Also a tool used for dressing Japanese rotating water stones.

Tsukareta – literally “tired,” a word used to describe a Japanese sword that has been sharpened over the years to the point where it is no longer serviceable because the hardened steel is all removed.

Hagane : Hard steel (usually the carbon core)

Jigane : Soft steel ( usually iron cladding or stainless cladding)

Hamon : Wavy line on Honyaki knives

Wa handle :Japanese handle

Yo Handle : western handle

Hawatari : Japanese term for blade length

Kaeri : Japanese term for Burr

Burr : Raised and curled lip of the metal that forms on the edge during sharpening. Burr always forms on the opposite side of the sharpened side of the edge. You can see it of feel it with your fingertip

HRC: Rockwell Hardness Scale – Nondestructive way of measuring steel indentation hardness by depressing a diamond crystal into the steel. Invented by Hugh and Stanley Rockwell. HRC value is measured by penetration depth of the diamond crystal tip (penetrator or indenter) into the steel with large load and comparing it to preload force penetration. Generally good knife blades have Rockwell Hardness at high 50s, low 60s for most of the modern steels. In short, the higher the hardness is the better wear resistance it but the blade becomes more brittle. Non steel alloys, such as Stellite, Talonite, etc. have lower hardness around 40s, resulting in low strength, but still have wear resistance due to their chemical composition, which doesn’t necessarily translate into high edge holding, especially on hard materials.

Kakumaki : Japanese term for a bolster collar or ferule. Traditionally made of water buffalo horn, although both, more expensive and cheaper materials can be used like Pakka wood.

Kiri : Cutter in Japanese, apparently derived from the word cut. Nakiri, Udon-Kiri, etc.

Koba : Japanese term for secondary bevel

Machi : Narrow section of metal between the notch at the end of the neck of the blade and the handle, approximately 5mm long. Found on many Japanese knives (from the Tokyo region), never on western knives. In general when the knife has machi, the specified blade length includes all of the knife blade up to the machi notch, not just from the blade Ago(chin, to the tip).

Mizu-Honyaki : Refers to differentially tampered Honyaki knives. Blade spine is covered with mud, which is allowed to dry, then the whole thing is heated to the desired temperature and quenched in water. Spine is softer and springy, giving the blade certain degree of flexibility.

Mine/Mune : Japanese word for blade spine

Nakago : Japanese term for knife tang, portion of the metal to which the handle is attached.

Ura : Back side of the single bevel knife. Typically, on Japanese single bevel knives Ura is concave, not flat, and referred as Urasuki.

Urasuki : Concaved surface on the back side of the single beveled Japanese knives. Helps to reduce the drag during cutting.

Omote : Edge side of the single bevel knife.

Saya : Wooden sheath, or scabbard for the knife. As usual, identical wood is used for the handle and saya.

Shinogi : Japanese term for the ridge line formed by the flat portion of the blade and the blade path.

Akatsuchidoro – a special red mud clay primarily used in Japan for construction but used in the traditional Japanese bladesmith shop for thinly coating blades before quenching.

Baikin – the Japanese word for germs.

Gokunantetsu – mild steel used primarily as a toughening outer laminate on Japanese laminated blades.

Hineribo – a bar or stick with a slot cut into it to torque twisted blades straight.

Kata-ha – literally “one edge,” a two-layer laminate usually consisting of a hard carbon steel layer and a soft gokunantetsu layer.

Kobuse – a style of blade construction, primarily found in modern samurai sword blades, consisting of a mild steel core with a hard carbon steel wrap around the outside.

Magebo – a bar or stick with slots cut into it to straighten a bent blade.

Shinogi – the ridge line separating the secondary edge on a blade from the blade flats.

Tagane – a hammer with very hard carbide bits used to straighten bent or twisted blades by displacing small amounts of steel. Also a tool used for dressing Japanese rotating water stones.

Tsukareta – literally “tired,” a word used to describe a Japanese sword that has been sharpened over the years to the point where it is no longer serviceable because the hardened steel is all removed.

Hagane : Hard steel (usually the carbon core)

Jigane : Soft steel ( usually iron cladding or stainless cladding)

Hamon : Wavy line on Honyaki knives

Wa handle :Japanese handle

Yo Handle : western handle

Hawatari : Japanese term for blade length

Kaeri : Japanese term for Burr

Burr : Raised and curled lip of the metal that forms on the edge during sharpening. Burr always forms on the opposite side of the sharpened side of the edge. You can see it of feel it with your fingertip

HRC: Rockwell Hardness Scale – Nondestructive way of measuring steel indentation hardness by depressing a diamond crystal into the steel. Invented by Hugh and Stanley Rockwell. HRC value is measured by penetration depth of the diamond crystal tip (penetrator or indenter) into the steel with large load and comparing it to preload force penetration. Generally good knife blades have Rockwell Hardness at high 50s, low 60s for most of the modern steels. In short, the higher the hardness is the better wear resistance it but the blade becomes more brittle. Non steel alloys, such as Stellite, Talonite, etc. have lower hardness around 40s, resulting in low strength, but still have wear resistance due to their chemical composition, which doesn’t necessarily translate into high edge holding, especially on hard materials.

Kakumaki : Japanese term for a bolster collar or ferule. Traditionally made of water buffalo horn, although both, more expensive and cheaper materials can be used like Pakka wood.

Kiri : Cutter in Japanese, apparently derived from the word cut. Nakiri, Udon-Kiri, etc.

Koba : Japanese term for secondary bevel

Machi : Narrow section of metal between the notch at the end of the neck of the blade and the handle, approximately 5mm long. Found on many Japanese knives (from the Tokyo region), never on western knives. In general when the knife has machi, the specified blade length includes all of the knife blade up to the machi notch, not just from the blade Ago(chin, to the tip).

Mizu-Honyaki : Refers to differentially tampered Honyaki knives. Blade spine is covered with mud, which is allowed to dry, then the whole thing is heated to the desired temperature and quenched in water. Spine is softer and springy, giving the blade certain degree of flexibility.

Mine/Mune : Japanese word for blade spine

Nakago : Japanese term for knife tang, portion of the metal to which the handle is attached.

Ura : Back side of the single bevel knife. Typically, on Japanese single bevel knives Ura is concave, not flat, and referred as Urasuki.

Urasuki : Concaved surface on the back side of the single beveled Japanese knives. Helps to reduce the drag during cutting.

Omote : Edge side of the single bevel knife.

Saya : Wooden sheath, or scabbard for the knife. As usual, identical wood is used for the handle and saya.

Shinogi : Japanese term for the ridge line formed by the flat portion of the blade and the blade path.