Actual example to make a Norishige like appearance on blades, tachi and
We have a chance to see the steel for Dai-sho blades under forging. Dai-Sho means long and short.
The steel block has completed the fold welding work. It is made from several quality of steels mixed complicatedly, in order to expect a Norishige like appearance.
The steel block is divided into two pieces, one for Dai blade, the other for Sho. Then they are constructed as the cutting edge of the blades. So this Dai-sho is going to be made as sisters.
The core steel for the blades are forged up. Then the core steel and the outer steel are constructed to one block by Kobuse style, and roughly drawn out.
The steel for Dai
The steel for Sho
The steel bars are drawn out to the length for the blades.
They are shaped with hammer.
The Dai and Sho blades are shaped with plane and file.
The blades are tempered in a silent night.
They are still on the temporary polish to see the result of tempering work. Curvature has occurred on the both blades.
The foundation shaping has done.
The smith made the double narrow grooves on the blades.
The both blades are polished up. The Dai is by the modern style, and the Sho is by the classical style.
These blades are sisters, but their characters are not the same. The tachi has Norishige like appearance, and the wakizashi doesn't.
Now we can study them comparing the difference.
blade length 78.5cm, curvature3.0cm, thickness at the base 8mm, width 33mm
blade length 53.6cm, curvature 1.4cm, thickness at the base 8mm, width 33mm
The steel layers must be the same on both blades, because they are sisters those are made from the one steel block. But the appearance of the steel are quite different, as no one may not find that they are the same steel. The tachi has a large layer pattern with visible jinie (steel particles), even in the hamon area. On the other hand, we can't recognize such a large layer pattern on the wakizashi. The steel layer is not visible, it looks full of tight jinie. The difference of the appearance is a difference of steel grain. It is not a difference of layer pattern. The grain of steel particles is effected by tempering work.
The difference of grains on the same layered steel suggests us the mechanism how nashiji-hada is brought up. (=> Nashiji-hada)