Manufacturing Process of Knives

The typical manufacturing process will be introduced with videos.

  1. 01Quenching
  2. 02Grinding
  3. 03Bolster polishing
  4. 04Wet Grinding
  5. 05Buffing
  6. 06Sharpness inspection
  7. 07Assembly
  8. 08Handle polishing
  9. 09Blade shape inspection
  10. For traditional Japanese knives Forging
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Blade blanks are heated to a high temperature of 1,050℃ or above in an electric furnace to be hardened. The hardness will be improved by quenching the heated blade. Afterwards, to stabilize its structure and improve wear resistance, it will be tempered to 200℃.



The blade is sharpened from its heel to the tip with a coarse grinding machine so that the knife will slice through food easily. Then, the surface of the blade is polished with a fine grinding machine to give it a beautiful finish. The polished blade will become stain resistant.

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Bolster Polishing

The bolster attaches the blade with the handle and prevents dirt from building up, improving its hygiene. The welded blade and the burnt bolster are polished by hand. The handle will be easier to grip once the joints become smooth.

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Wet Grinding

The thickness of the blade is reduced by grinding with a coarse grindstone. This will give the knife a lighter cutting motion. In addition, the finishing sharpening will give the blades a mirror-finish, which reduces the resistance between the blade edge and food. Since the hard material is finished with a fine grindstone, it is difficult to determine the amount of pressure that needs to be applied on the blade, making it a process that requires the skill of craftsmen.

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Once the blades are sharpened, they will be left with a “burr”, which is a thin layer of ragged metal raised on the edge. Placing the burred edge on a leather buffing wheel will chip it away and give a smooth edge.

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Sharpness Inspection

The sharpness of the knife will be quantified to manage its quality. A constant load is applied on the knife to slice through a stack of paper. The number of sheets that were cut will be compared with the reference value to check the condition of the blade edge.



Pakka wood used on the handle is water-resistant and durable, making it suitable for cooking. The handle is attached to the blade with three rivets.


Handle Polishing

The knife is polished to flatten any unevenness between the assembled handle and blade so that it fits well in the hand when gripped. The edges are carefully removed to create a beautiful curved surface


Blade Shape Inspection

The blades made by the craftsmen are measured quantitatively. Using measuring microscopes, the inspection will assess whether the blade edge has the most suitable angle and shape for a knife. The measurement data will be used for further research on “sharp cutting tools” and to improve the skills of craftsmen.

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For traditional Japanese knives


Process of shaping blades for traditional Japanese knives. The ancient Japanese technique of swordsmithing that has been passed on to our generation. Steel is heated and hammered to make a long blade. The metal structure is refined by hammering, which creates a harder blade.

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