Newsgroups: rec.crafts.metalworking
Subject: Japanese Sword Stuff
From: blackhmr@alpha1.csd.uwm.edu (Robert M Van Rens)
Date: 19 Oct 1994 17:34:02 GMT

Well, I got such a huge mail bomb I decided to post this information to the
newsgroup and just forget about it, so PLEASE stop sending me mail on this
subject; it's nice to chat with people, but two dozen messages a day is
expensive and time-consuming to read...

Here'e a brief synopsis of a paper on Japanese sword-making that I wrote,
including some of my notes on the experimental proccess in which I engaged
to make some samples, which turned out quite well...

I.  The Steel

"Tamahagane" is what the Japanese call the steel they use for making their
swords.  Essentially it is smelted from river sand in a charcoal smelter
called a "tatara". Optimal temp in tatara is around 1200 degrees C, which
drains off all the slag, but allows some of the charcoal to combine with the
blows of iron, resulting in a mass of steel and iron with uneven carbon
content.

The smith then takes the chunks of tamahagane and breaks them up with a
hammer, sorting them out by approximate carbon content.  He does this by
inpecting the fracture zones, and the pieces with finer crytalline structure
are set aside for use in the sword.  Those softer pieces that are left are
used for toolmaking, or are re-smelted for better quality.

II Forging the Steel

The steel of the sword consists of one large peice of lower-carbon steel,
and many smaller pieces of the higher-carbon tamahagne.  These are wrappeed
in paper and clay (hence the "paper" classification of the blades; blue
paper for common, green paper for nobility, and white paper for the Imperial
family or Shogunate.  The rituals change a bit with each method, but the
construction techniques remain essentially the same) and heated to a welding
temperature, then fused into a block.  The welding is done in a charcoal
forge, at a much lower temperature than Western smiths would beleive
possible.  However, the clay not only acts as a flux and anti-oxidant, it
also insulates the block and allows it to retain the heat better.
Conversely, it also makes the heating process go slower.

The smith then notches and folds the block, welding it each time to help
distribute the carbon more evenly throughout the blade.  The direction in
which it is folded is important, foir it will help determine the pattern of
striations in the blade later.

In some cases, the piece is folded in half and a higher-carbon piece is
insertd to form the edge, or a lower-carbon piece may be inserted in the
back to help improve flexibility and resist breakage.  At any rate, the
blade is drawn out with a very slight curve, nowhere near the arc it will
eventually have.

The bavel is now roughed in, and the piece is cooled.  When it is done
cooling (annealing, actually), a high-carbon plane is used to shave away
irregualrities in the surface of the steel and smooth out the piece.  When
the smith is satisfied with this, he moves on to the next, and most
important step.

III Tempering the Blade

This is absolutely the single most important part of forging the Japanese
blade, and one which has been mis-interpereted countless times by all sorts
of observers, and discounted by othwers as not important.

The smith begins by coating the balde in a clay slurry about half an inch
thick on either side.  He then scrapes away from the edge much of the clay,
resulting in a wedge-shaped bar of clay with a steel core, and the edge of
he blade at the edge of the wedge of clay.  About a quarter inch in fron the
edge, he puts on an extra thin line of clay, which will become the features
known as "ashi"

The blade is then heated in the fire and quenched in water.  The process is
not actually tempering; that is it is not the heat-traeting after the
ardening; instead, it is the hardening process.  The bright-red hot piece is
plunged into a trough of water.  THe edge, of course, hardens first, become
very strong and tough.  The parts better insulated by the clay harden
somewhat slower, allowing them more time to contract and toughen, giving a
blade with great strength and toughness that will resist shock and not
shatter on impact.  This is where the curve in the blade comes from.


At any rate, a sword not made by these methods is not really a Japanese
sword, and is not worth the price you would pay for a true tachi.  It was
suggested that you should expect to pay upwards of $1000 dollars for a good
tachi.  I personally acquired a short blade (wakizashi) as a gift from one
of the smiths I spoke to concerning the research project I did.  It was
appraised by the Japanese government's Ministry of Culture at around $2500,
and it is considered a mediocre quality blade at best.  It is phenomonally
difficult to acquire a full-length katana outside of Japan; if it is the
work of a true master of the craft, which it must be to be sold, it will
easly run $10,000 or more.  If you can find one.

In addition to interviewing Yoshindo Yoshihara-sensei, Jinjiro Motohama-
sensei, and Tadatsugu Shimuzu-sensei, I used the following books for
research;

The Craft of the Japanese Sword 
by Leon and Hiroko Kapp and Yoshindo Yoshihara
	(yes, the same one I spoke to)

The Samurai Sword, a Handbook
by John M. Yumoto

The Arms and Armour of the Samurai
by A.P.Hopson and I. Bottomly

The Edge of the Anvil
by Jack Andrews
	(extemely incredibly useful for applied metallurgy and temperture
	 refernce charts, and one of my most treasured books)

And a whole stinkin' lot of experimentation and failed attempts before I
found a proccess that produced a comparable product to the steel made by
Motohama-sensei, who graciously sold me tamahagane at $40/kg (less than the
going rate, mind you) and presented me with a sample of his own steel and a
blade when I finished my first one, and to whom I owe a great debt of
gratitude.  On the offhand chance he may hear of this through a collegue,
domo arigato gozaimashita, sensei.

This is, of course, a terribly shortened version of my work, but I am
operating under a time constraint and have to go now.  So any questions,
post them and I will attempt to answer.

Robert Van Rens
blackhmr@csd.uwm.edu

Newsgroups: rec.crafts.metalworking
Subject: Re: Japanese Sword Stuff
From: blackhmr@alpha1.csd.uwm.edu (Robert M Van Rens)
Date: 21 Oct 1994 14:28:22 GMT

I am afraid that I do not read kanji over the Net, so I have absolutely no
idea what the markings on the hilt mean...however, if it is really an
Imperial Chrysanthymum (five lobed petals, I think, or was it seven?  I
forget, and don't have the book right here), then it quite possibly belonged
to a member of the Imperial Family, or a favorite of them...but I do not
claim to know all, or even close to all, about the markings...I am a
blacksmith, not an appraiser.  I do know that if the hilt is stamped, then
it is the work of an acknowledged master.  Gendaito (New Style Swords),
pre-WWII, are fairly valuable, but nobody knew this at the time of the
surrender.  That is why there are a fair number in collections in the USA.
They are still exceedingly difficult to acquire.  BTW, the porices I quoted
are for newly-forged ones, not antiques, which are hideously more expensive
and even more difficult to acquire.

Robert Van Rens