Blade Material: 1095 high carbon steel
Forging Craft: hand forged and polished by 13 procedures, clay tempered
Hamon: real hamon, clay tempered line
Tang: full tang
Blade style: Unokubitsukuri鵜首造,"小烏丸"
BO-HI: Double bo-hi,a long and a short one
Whole length: about 50 cm
Blade length: about 30 cm
Nakago length: about 19 cm
Weight: 346g
There is no hole on nakago.
Forging Craft
This blade is 100% hand-forged and hand-sharpened according to the Japanese traditional forging methods. Our differentially hardened carbon steel blades have been heat-treated, sharpened, and well-balanced. The blade is constructed from high quality carbon steel, carefully hand beaten into shape, forged, quenched before being polished by hand to a mirror sheen.
Clay Hardening
Before being quenched, a special clay mixture can be applied onto the blade to harden the edge and obtain different hardness on the blade. The clay mixture, was a special recipe and considered a crucial trade secret, guarded protectively by sword making masters.It would contain such things as feathers, powdered bones, grass, etc. and would be applied to the edge of the blade before being quenched. During quenching, a chemical reaction between the clay mixture and the hot steel occurs during the sudden temperature drop and carbon is fed into the blade in high amounts, creating an extremely tough edge. A clay hardened blade can only be quenched in water, thus increasing the defect rate even more.
Another way for clay tempering is to apply clay along the blade but let edge exposed. Thus, while quenching the blade into water, the uncoverd edge will cool down suddenly, but the rest of blade will cool down slowly. Such differential temperature change results in the different hardness of the blade. So the edge is tough enough to cut, where the back of blade is soft/flexible enough to absorb the impact during cutting. Such quenching process usually will leave beautiful wavy tempered line on the blade, as known as "homon" in Japanese swords term.
Tempering
After quenching, the sword will be quite tough and brittle, with little flexibility. To overcome this, the blade would undergo a tempering process. The blade would be reheated to a certain temperature degree then allowed to cool naturally. The blade would be slightly less tough afterward but have a greater degree of flexibility – the art would be to perfectly balance the blade for toughness, sharpness and flexibility.
Full Tang
While it is common to find swords which have a rat tail tang (two pieces welded together), a thin tang or even no tang at all, all of our Japanese swords have a thick tang running from the blade to the full length of the handle.
How to appreciate blade quality
Generally, we appreciate blades with the three elements. At first shape, then steel, and then hamon.
1) Shape
You must take an over-all look at the blade first. Seeing the shape completely is very important to appreciate blades. It should be well-ordered from the bottom of tang to the top of kissaki.
All the elements of the blade are condensed to its shape. So understanding the distinction between good shape and poor shape is necessary to know its quality.
For the good shape, every line must be smooth and sharp, every surface even, and full meat is kept on the cutting surface. And the harmony of the whole shape is most important. A good shape will come from good steel and good tempering. It illustrates a sense of the smith.
But it is difficult to explain the "shape" by words or images. "Good shape" doesn't mean some design of blade. It is general word used for every kind of style of blades.
2) Steel
Steel is a base of blade quality. A good steel is necessary for good shape and for good tempering effect. It is not a meaning of layer pattern.
3) Hamon
Various types of Hamon patterns are attractive for beginners eye, but to see the quality of hamon is far more important. Utsuri (shadow of hamon) also can be seen by this way. Real colours come up.
Hamon pattern is not a matter for blade quality. Difference of hamon pattern means just a difference of pattern, never mean difference of quality. Hamon is the most visible appearance of the sword. Looking at it is very interesting. Hamon is a big factor of the character of a blade. Its pattern is very attractive for beginners eye. But, the pattern does not mean the quality. An aesthetic hamon pattern doesn't mean a good hamon. It is just a matter of liking. The brightness and the fineness of the hamon, not only the hamon line but also the hamon area, is a bigger criterion of the quality.
HOW TO TREAT THE BLADE?
Japanese blade is made from the pure steel, and is completely polished. So, suitable treatment is necessary. Because the surface is delicate and the cutting edge is very sharp.
The blade should be always coated with good oil. And we never touch the blade with naked finger.
Please do not put the blade on a carpet. Please put it on a clean table cloth and use some soft cloth or paper as a pillow for the blade.
Careless treatment makes scratches onto the blade surface.