| Step 1 - Rough Forging |
The blade is forged by hot forging a billet of
super high carbon steel into the shape seen here. The repeated
hammering provides an even dispersion of carbon throughout the steel
for uniform strength of the finished blade |
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| Step 2 - Rough Shaping |
The scale is removed and the blade is shaped
roughly to the required dimensions. At this stage, the steel is still in
the annealed (soft) state and the blade is straight. |
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| Step 3 - Clay Covering |
A special clay is applied to the blade by hand,
using a thin covering near the edge and a thicker layer over the rest of
the blade. This results in a relatively quicker cooling of the edge during
quenching, producing a harder cutting edge and a softer back (spine). |
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| Step 4 - Quenching |
This is a critical part of the operation. The
blade, with its clay covering is heated to a predetermined temperature and
quenched in a water bath. The shape and continuity of the hamon, the sori
(blade curve) and blade straightness are all determined by the care
and skill exercised in quenching. |
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| Step 5 - Sizing |
The sori is adjusted if necessary, to set the
point of balance and point of percussion. The blade is the de-scaled.
Rough polishing is carried out to size the blade accurately. The habaki is
then fitted. |
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| Step 6 - Finishing |
Careful final polishing and fine finish work are
carried out on the various surfaces to define ridge lines and bring out
the beauty of the hamon. |
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