Truth of a Japanese sword 0

The outline of a Japanese sword

　Search in a pageSearch 　About a Tamahagane | Sword making (structure) | Forging and intensity

Now, the conditions of the Japanese sword recognized in the world are very partial.
A sword community mentions the following three points as conditions for a Japanese sword.

January 8, 2014January 8, 2014January 8, 2014 　　1. Steel materials:   Use steel materials are Tamahaganes.
　　2. Cuff forging:   Steel will become strong if there is much forging.
　　3. Core structure:   The structure of a blade wraps soft Core structure in hard steel.

The method of this structure is how to forge the Shin Shin-tō of the Edo last stage.
This fixed concept has permeated strongly among Japanese sword persons concerned.

However, the peak of a Japanese sword is a Ko-tō.
A Ko-tō differs from the conditions of a Shin Shin-tō.
Nevertheless, the sword community in Japan has continued saying that a modern Shin Shin-tō is a sword of Japanese ancient times.
This fixed concept has permeated strongly among the sword persons concerned.
This is the reason which was not able to reproduce a Ko-tō.
I prove that three conditions of a sword community are wrong.

Indication to the Japanese sword of a Kōkan Nagayama polisher

The polisher of the sword knows the character of the steel materials of a Japanese sword best.
He is a living national treasure.
He has sounded the alarm bell to how to forge the Japanese sword after World War II.

　　　　　　Kōkan-Nagayama polisher

　Indication of a Kōkan-Nagayama polisher.
{ The postwar swordsmith has set the fine-arts sword as the purpose of a
sword making.
The purpose of the sword was to forge not arms but a work of art.
However, I regard this as it being a fundamental mistake.
The way of thinking of "making a work of art" is a fundamental mistake.
Don't misunderstand my opinion. I do not claim these days "make a weapon."
However, a Japanese sword is a weapon and has progressed.
A Japanese sword is equipped with fine-arts nature as such a result.
Therefore, the swordsmith must put the starting point of a present sword on
the "weapon" instead of a "work of art."

........... From a polisher's viewpoint, he raised the example of the Ko-tō, the Shin-tō, and the Shin Shin-tō, and has explained the reason concretely. (abbreviation).......If reappearance of a Ko-tō is aimed at, the swordsmith must throw
away the method of a Shin-tō. And the swordsmith needs to explore another method. (Abbreviation) .........

If a swordsmith aims at reappearance of a Ko-tō, it is necessary to throw away the sword making after a Shin-tō and to explore another method. The sword after a Shin-tō does not almost have a difference for every school.
It is the position in which make a ground metal by the fixed method and only a Hamon is hardening by the Sosyū-style or
the Bizen-style.
Therefore, only a fixed style appears.
There is the style "Hitatsura of a Sosyū style" in the Period of the Northern and Southern Dynasties.
That is the Hamon which a ground metal has a device and was so produced. The steel with which character differs is mixed variously and there is also a portion in which hardening is not contained in the edge.
Even if the blade is whole hardening , it does not interfere.
"Hitatsura" which future generations hardened intentionally is differed from. If an early Japanese sword and an early sword are seen, it is not new that a spot is in an edge or there is a part in which a temper is not contained.
It depends on the used material.
It was derived that it uses sorting out steel in quality, after the time fell considerably.
Masamune applied the principle of the sword of an old time intentionally from a viewpoint of a function, and it was completed to a style called Sosyū-den.
Thus, if it considers, the sword making of the time of an old noted sword will be considered to have been unexpectedly childish.
The Gendai-tō was caught by the idea of making a work of art, too much.
Therefore, it has lapsed into the too strict sword making by extension of a Shin-Shin-tō. }

Nagayama, a polisher, says. "Therefore a Ko-tō is made by the childish sword making using the steel materials which mixed different steel, consequently the beauty of the grain of a blade can be expressed".
He has proposed throwing away the common sense of the steel materials and a sword making which have spread now.
The meaning of this language is heavy.
We will notice reference made by the abyss of a Ko-tō, if every word of his proposal is read carefully.
It is presumed that Heian and the Kamakura period when iron-manufacture technology is low, and the temperature in a furnace of a Tatara did not reach an iron dissolving point.
Therefore, it is surmised that distinction of steel, iron, and pig-iron was not certain, either.
Swordsmiths elaborated this mother material and made the Ko-tō.
In the Edo period, although technology progressed and exchange of swordsmiths' information progressed, the level of a sword was surely less than the Ko-tō. Many polishers indicate that the ground metal of a Ko-tō is softly pliant, and the beauty of the skin of a blade is brilliant.
The hardness of the edge of a Ko-tō is almost the same as the core steel of a Shin-tō.
Although the quality of the blade of a Ko-tō was soft, there was a toughness. Compared with the Ko-tō, the Shin-tō was hard, the Shin-Shin-tō became still harder, and the grain of the blade became monotonous with minerals.
Becoming a Shin-tō, therefore, swordsmiths came to make a sword to the same steel materials (mass-production Tamahagane) and the same sword making.
This means "standard fertilization". The individual special feature of a sword was lost only in the difference in a swordsmith, and the difference in a Hamon.
A mass-production Tamahagane must recognize the reality in which the deepness of a broad Japanese sword and the beauty of a grain of the blade have been atrophied.
Many of present age swordsmiths also have the reason aimed at a Ko-tō here.
The mystery of a Ko-tō cannot be solved by modern science, either. A Ko-tō is wrapped in a mystery.
It is a very ironical talk that the "Tamahagane myth" and "the common sense of a sword making" after a Shin-tō have barred reappearance of a Ko-tō.

The mistake in the common sense of a Japanese sword

About a Tamahagane

High temperature was not obtained by the time of a Ko-tō in a Tatara iron mill. For the reason, pig-iron, iron, and steel were made harmonious.
Swordsmiths did serious devise, in order to make a good ground metal(Jigane).
Therefore, there is a difference in steel materials for every swordsmith and every school, and the difference of the ability of a swordsmith arose.
The beauty and the excellent performance (it is pliant and strong) of a blade was realized in combining steel materials of a different kind.
The hard Tamahagane of mass production appeared in innovation of the Tatara of the Keichō age (Around 1600).
An iron mill sorts out steel and came to supply it to a swordsmith.
Therefore, the primitive Tatara iron mill declined and changed the supply organization of steel.
It was forced by swordsmiths to use this Tamahagane without acceptance or declining.
Since this Tamahagane was too hard, the conventional sword making stopped accepting.
Then, the structure of a new blade was invented (laminate constraction).
Since the labor of the swordsmith for devising a ground metal was mitigated, they may have supported this Tamahagane.
It seems that use of the southern barbarian iron imported at the same time supports this.
The word "a good thing becomes impossible if people begin to live in comfort" is tinctured with sincerity.
In the middle of the Edo period, the still harder Tamahagane of mass production appeared in improvement of a Tatara.
Did these mass-production Tamahaganes contribute to improvement in arms performance and blade beauty ?
Reality was reverse rather. Compared with the Ko-tō, it was proved from testimony of a polisher and a martial artist, and verification in a battle that the performance of a sword and the beauty of a blade were retreating clearly
"Iron and a man worsen as a time falls" is truth. A sword is still less than the level of a Ko-tō.
The Tamahagane myth obstructs it.
2

Sword making (structure)

A sword community despises an one-piece forging and is praising itself in the blade structure of a laminate constraction. However, this is a big illusion.
Since the mass-production Tamahagane was too hard and fear of blade breakage arose, it is only the sword making that newly had to be devised. And a three-sheet forging and four-quarters stuffing were the simple techniques for mitigating the labor of a swordsmith. In spite of the simple technique, it was the sword making of the inconsistency which may be able to do an extraordinary swordsmith barely applying serious time and effort. The blade which the laminate constraction completed has heterogeneous distribution of hard and soft steel, and the 80 - 90% is not as an ideal.
With the expected ideal, it is finished in the dangerous blade which was widely different.
Moreover, this laminate constraction was unsuitable for the battle.※ (see to "research of a blade of the Guntō")
The combination forging of the hard and soft steel which is in others in some numbers excelled this in practical use.
Steel materials of a different kind are combined skillfully, and it also turns out in the battle that the old noted sword of the one-piece forging which elaborated the hardening was excellent. The spring sword of an one-piece forging was excellent in the arms performance with the toughness and hardness of steel materials.
It is only the superstition that is said that an one-piece forging is useless.
It became a peaceful world from the Shin-tō term, the sword was used for the battle, and it was lost.
If the Shin-tō has appeared at the Warring States term, It seems that it was screened immediately.
The possibility of enough existed. The swordsmith in which the present age also aims at reappearance of a Ko-tō challenges manufacture of an original ground metal, and does not use a mass-production Tamahagane.
A Tamahagane is one mere choice in the steel materials for Japanese swords.

← The blade section of "Yasuhiro Kobayashi" of a present age swordsmith.
   The Kobayashi swordsmith aimed at reappearance of the Ko-tō.
   This blade is the one-sheet forging which "kneaded together" hard steel
   and soft steel. This is famous as "a sword which tears apart iron."
   　　　　　　　A right photograph is a blade section of a Guntō. →
      　　　　　　Left:   One-sheet forging of alloy steel.
　　　　　　　　　Center: Two-piece structure of hard steel and soft steel.
　　　　　　　　　Right: Laminate construction based on a Shin Shin-tō.

The upper blade section showed the general example for every era. There are structures other than this by the school
of a swordsmith.

Introductory notes

   One-piece forging: "Kneading together" of hard steel and soft steel.
　　　　　　　　　　① Generated by chance as a result of childish smelting (Ancient times - a medieval early)
　　　　　　　　　　② Refine pig-iron and am generated. The main steel materials of a Ko-tō. (Medieval times)
　　　　　　　　　　　　Use a part of present age swordsmith which challenges reappearance of a Ko-tō.
　　　　　　　　　　③ Knead hard steel and soft steel intentionally, and generate them (Present age)
　　　　　　　　　　④ Add and generate effective metallic elements. Alloy steel according to the performance purpose.
　　　　　　　　　　　 The ultimate steel materials of kneading together. (Present age, used for many Guntōes.)

　 Two-piece construction: "Pasting" of hard steel and soft steel.
　　　　　　　　　　　　This structure was used from ancient times in the world, in order to secure the tough nature of
　　　　　　　　　　　　a blade.

   Laminate construction: Wrap core of soft steel in hard steel.
　　　　　　　　　　　　The Japanese steel which appeared just before the Keichō era was an iron material of high
　　　　　　　　　　　 carbon. If the one-piece forging of this is carried out, a blade will break.
　　　　　　　　　　　　Therefore, the structure using soft steel to core was devised.
　　　　　　　　　　　　However, the sword after a Shin-tō was inferior in the battle line of China compared with the
　　　　　　　　　　　　Ko-tō.
　　　　　　　　　　　　Furthermore, since the balance of hard steel and soft steel will collapse if polish decrease is
　　　　　　　　　　　　carried out, the sword of this structure is unsuitable for battle use.


In order to secure the intensity of a blade, the swordsmith devised and forged the sword from ancient times.
There were two methods in it.
　　　1. Knead together hard steel and soft steel.
　　　2. Paste hard steel and soft steel together. This device does not ask the east and west in the world.
Many Ko-tōes were the complex tissues by which steel of the different amount of carbon was kneaded.
This is the result of depending on the childishness of iron-manufacture / refinement technology.
The blade of this One-piece forging is battle verification of the China incident, and that outstanding performance is proved.
The secret of "the beauty of toughness and natural complexion" of a Ko-tō has a reason in a heterogeneous blade structure which hard steel and soft steel kneaded together.
The blade which kneaded different-species steel together was excellent in the performance compared with the blade of "put two sheets together" of homogeneous steel. As long as the hard Tamahagane of the uniformed mass production is used, an One-piece forging is inferior. Therefore, the laminate construction of hard steel and soft steel was devised.

However, as this structure was mentioned previously, there was a fatal defect.
Therefore, a radical examination of a lower blade surface Jigane is needed.
When the steel materials and manufacturing process of the Ko-to could not be solved, the special steel for swords which improved pliability and tough nature chemically was the one solution.
The fine-arts sword community in Japan despises the One-piece forging.
This is because the sword community is ignorant.
The spring steel sword of the One-piece forging was excellent in the weapon performance.
The character of the steel materials used for a blade determines the superiority or inferiority of an One-piece forging.
If it is the alloy steel which added the useful element, it is not necessary to unite different carbon steel.
Many special steel is proving it.

Except the kneading material of hard steel and soft steel, a two-piece sword construction is practical.
The sword community in Japan says that a three-piece forging or "four-quarters stuffing" is high-class structure.
It is a recognition mistake and is only an empty theory.
Fortunately, a sword is no longer used in the world of an Edo peace.
If the Shin-to had appeared at the Warring States term, the blade exposed the defect and, probably, was immediately screened.
A Japanese sword community advertizes this laminate construction with the feature of a Japanese sword.
And a sword community claims that this is the traditional structure from a Ko-tō.
This is entire fabrication.
The laminate construction was a degenerated structure as a Japanese sword.

The steel materials of a blade, and comparison of the intensity by structure

The Japanese version explains the basis of this comparison in detail.

Relation between a forging and blade intensity

In order to acquire the qualification of an army commission swordsmith, the swordsmith needed to meet the fixed standard of the intensity of a blade.
Charpy type drop test equipment is used for a strength test official. As shown in the next figure, an inspector lays a blade between pillows.
And an inspector drops about 11.25-kg weight from a top, and inspects that a blade bends.
Height is inscribed on the pillar of a testing machine.
When a blade breaks, an inspector does division of the fall weight (kg) of weight in the area (sq cm) of the portion which broke. The value is a "Charpy impact value."

There is "shock value" data which charms interest very much here.
The examination results by the piece of steel forged of the almost same conditions as a Japanese sword are as follows.

The Charpy type drop
impact test machine


The number of times of a cuff forging	Shock value	Remarks
(1) No forging (Sunobe)	2.42
(2) Once fold (steel forged to the original length by bent two)	4.88	A shock value improves by leaps and bounds (tough)
(3) Twice fold (same as the above)	5.07	The improvement in strength is a slight increase
(4) 3 times fold (same as the above)	2.42	The strength of a cuff forging does not change after it

This experiment to a cuff forging is not improvement in intensity.
The purpose of a forging is the adjustment of the amount of carbon and the removal of impurities
which are the fate of primitive direct iron manufacture.
This experiment to a cuff forging is not improvement in intensity.

The purpose of a forging is the adjustment of the amount of carbon and the removal of impurities which are the fate of primitive direct iron manufacture.
This is the primitive technique for refining rough iron of iron manufacture to steel.
In ancient times, it was a universal technique.
That is, this is not a peculiar technique of Japanese sword manufacture.
If there is steel adjusted beforehand, there will be no necessity for a forging.

Another experiment

Toshihide Horii of the swordsmith famous to the early of Showa Era examined the forging together with Tomitarō Satō.
Tomitarō Satō is a researcher of a Japanese sword.
I show the result briefly. (I describe detailed data to a Japanese version)

Conclusion
1. A Tamahagane is the rough iron generated by childish iron
manufacture. The Tamahagane contains physical impurities.
Even if this carries out 12 to 15 times of forgings, the
improvement in strength is 30% at its maximum.
2. Even if it carries out the forging of the steel already
adjusted by refinement, there is no change of strength.

Army drop test results

In the army Sagamihara arsenal, the strength test of the sword of a Tamahagane laminate construction and the sword of the one-sheet forging of the Gunsui-steel generated at the electric refinement furnace was carried out.

A result calls at the next table.


fall height / A swordsmith name	15 ㎝	25 ㎝	35 ㎝	45 ㎝	55 ㎝	65 ㎝	75 ㎝	85 ㎝	95 ㎝	100 ㎝
Hideaki Kurihara	0.25	0.49	0.85	1.30	1.69 Edge deficitX1	2.07 Edge deficitX1	2.59 Edge deficitX1	- Edge deficitX1	3.39	4.17
Shōhei Miyairi	0.16	0.24	0.44	0.89 Edge deficitX1	1.12 Edge deficitX1	1.54 Edge deficitX1	1.89	2.22 Edge deficitX1	2.66	3.04
Akinobu Hatano	0.30	0.59	1.00	1.40	2.00 Edge deficitX2	2.54	3.08	3.58	4.40 Edge deficitX3	4.68
Gunsui-tō	0.13	0.14	0.24	0.44	0.72	1.02	1.27	1.54	1.96 Edge deficitX1	2.16 Edge deficitX1

Three upside Japanese swords: The sword of the laminate construction of a Tamahagane.
Gunsui-to: Gunsui-steel use which Gunsui Electrification Industries manufactured with the electric furnace.
One-sheet forging.

The sword of the laminate construction of a Tamahagane produced the edge deficit from the early time.
The Gunsui-tō became the last and produced the edge deficit.

Hikosaburō Kurihara examined the Gunsui-tō in advance of this examination. He was governed by the concept of the Shin Shin-tō as well as other swordsmiths.
He forged two kinds of 30 Gunsui-tōes respectively.
　　1. Gunsui-to of an one-sheet forging.
　　2. Gunsui-to which carried out forging of Gunsui-steel, and was made into laminate construction.
The experts of the sword of the era tested trial opening with these swords strictly.
As a result, as compared with the sword of a two-piece sword construction, the sword of an one-sheet forging without a forging did not have the difference of blade intensity.
Hikosaburō Kurihara accepted the reality obediently.
Hikosaburo Kurihara is a Diet member in wartime. And he was a leader of Japanese sword revival.

The fine-arts sword community in Japan continued claiming that the sword of the laminate construction of a Tamahagane is the strongest. It was proved that it is falsehood.

　　　　　　　　　　　　　　　　　　　　　　December 12, 2013　

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