Koharu-130 Mini Santoku

The Koharu-130 is a thin and short blade santoku made using the "warikomi" technique - where heated soft steel is split in order to insert the hagane (high carbon cutting steel), before it is hammered together to form a thin sandwich of two steels. The knife has a 130mm long blade to allow for tasks associated with both santoku and petty (paring) style knives. It is forged, sharpened, assembled and boxed by Daisuke Nishida, a sole blacksmith working from his studio in the Tamana district of Kumamoto prefecture.

• Blade steel: Shirogami (White Paper Steel) No. 1
• Blade finish: Kurouchi (Blacksmith) finish
• Blade length: 130mm
• Total length: 265mm
• Handle: Octagonal walnut
• Packaging: Black and red cardboard box

Please note: These knives are made individually by hand. The finishing on each blade is unique. The knife you receive might therefore not have the exact colour or pattern as in the picture, but it will be in the same style.

This is a carbon steel knife with no stainless protection. It will develop a patina with use and it is important to wash the knife  by hand after use, and to dry it well. By caring well for the knife, it can become a long-time favourite kitchen companion.

Nishida knives are made in small batches and stock is limited. If sold out, we can enquire about individual stock items. Please email us at info@wazashop.co.za to request a pre-order.

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At age 19, Daisuke Nishida began an apprenticeship under another blacksmith for nine years until he set up his own studio. He has 24 years of hand-forging experience and is passionate about protecting the traditional "honwarikomi" forging method, which requires extensive effort and skill. This passion for traditional forging is expressed by crafting each blade entirely by hand, resulting in a unique lustre and look for each blade and a sharpness that makes it a special kitchen tool.

In Nishida san's own words, the forging process follows the following steps for a mirror-finish knife:

1. "Raw material preparation: The traditional Japanese manufacturing method, "wari-seiho," simply uses two materials: steel and jigane. The steel and jigane to be used are selected according to the purpose of each blade.
2. Interrupt: The heated jigane is cut, the steel that will become the blade is inserted, and then forged into a three-layer structure of jigane + hagane + jigane. After this, the steel is further forged until each material is firmly bonded together.
3. Cutting out the material: The material that has been forged into a three-layer structure is stretched into a long, thin plate. It is then lightly heated in a furnace, and once softened, it is cut into pieces the size needed for one knife.
4. Mold making: The material cut out for each blade is heated and the forging process is repeated 3 to 4 times, and the blade is quickly shaped with a hammer before the carbon is removed from the steel and it loses its inherent strength.
5. Annealing: In order to even out any unevenness in the structure caused by the force applied in steps 2 to 4 and return the blade to a normal state, the blade is heated to 500-700°C, then placed in straw ash and allowed to cool slowly overnight.
6. Quenching and tempering: The knife is hardened by applying mud and then "water quenching." The knife is slowly and evenly heated to the optimum temperature of 790-830°C, and then quickly plunged into "water" to rapidly cool. At this point, the steel structure tightens, resulting in an extremely hard structure. The temperature control for hardening is done based on the color of the reddened knife, so it requires many years of experience and intuition. Hardening is a real challenge, as even the slightest deviation from the timing will result in failure and the knife will become scrap metal. In its hardened state, the steel is very hard, but at the same time brittle and prone to chipping. To make the blade tougher, it is heated again at the optimum time and temperature for each type of blade.
7. Rough grinding: First, the knife is clamped between the sharpening board and the steel is roughly sharpened using a coarse whetstone, then the knife is held in the hand and, with delicate adjustments to the hand, the steel is sharpened evenly.
   Finishing polishing: The rough sharpening does not yet produce a satisfactory cutting edge, so we carefully sharpen it by hand with a finer whetstone to give the surface of the sharpened area a sharper finish.
8. Name: We stamp the knife with a mark.
9. Patterning: The part of the knife that fits the handle is heated until it becomes red, and then the handle is inserted. The bottom of the handle is struck with a hammer, and each knife is adjusted one by one to the angle that is comfortable to hold and use, while the handle is tempered."