From: maxson@cerl.uiuc.edu (K R Maxson)
Subject: Re: What is with these Katana's?
Organization: UIUC Computer-based Education Research Lab
Date: Mon, 31 Aug 1992 19:02:30 GMT

In article <1992Aug31.162510.26957@burrhus.harvard.edu> canders@isr.harvard.edu (Carl E. Anderson) writes:
>	Now if I recall correctly the katana's and similar designs had a
>soft iron core with a very hard steel case and edge which gave both
>flexibility and cutting power.  This seems roughly analogus to the Western
>pattern welding.  I'm not sure that forging technique is at issue here.
>	Now I've seen a lot of "long swords" and a lot of katanas and
>discussed them with people who know much more about it than I (thus my
>original question :) and boy are there some _shitty_ katanas out there.
>There are some _shitty_ "long swords" too.  Or about as many of one as the
>other.  (Luckly most of the surviving examples are the better ones).

First, a general description of Japanese blademaking.  Then a general
description (briefer, since I assume people are fairly familiar with it)
of European blademaking.

IN JAPAN

The steel used to make blades was generally impure magnetite smelted in
blast furnaces for 4 days.  One sixth of the metal, the stuff on top, would
be burnt and useless, and it was discarded.  One third of the metal would
be steel, ranging from hard to soft; the remainder would be cast iron not
used in blademaking.  The steel mass would be broken into smaller pieces
and the smith would select those of the desired hardness and weld them into
bars.

For poor swords a bar of iron was welded to the edge of a wider bar of
steel so that the steel would form the edge of the blade.  This was suyeha
and was used only for the worst swords.

Another method was to split the edge of a bar of soft metal and weld a hard
one in the cleft; this was called wariha.

In kobushi a bar of iron with a wedge-shaped edge was inserted in a bar
of steel doubled into a V section and welded in place.

In the uchimaki method (also called awase ni mai) a kataha was doubled
back on itself to bring the steel surfaces together and welded.

In moroho, a strip of iron was doubled around the edge of a bar of steel,
leaving the edge of the steel bare, and welded.

None of the above methods produced first-class blades.

In the ori awase san mai method, a bar of steel was placed between two
bars of iron on an iron plate the width of the three.  It was welded
and doubled so as to bring the steel to the steel, welded and forged.

In the shihozume, two plates were made by doubling and welding two
kataha 15 times.  A narrow plate of hard steel was placed between one
edge and the remainder of the space filled with an iron plate; the
whole was then welded and forged.

Masame and nogi-hada took a kataha, douibled it on itself and welded,
repeating 15 times and yielding 32,768 layers in the bar.  If the bar
was forged by striking the edges of the layers it was called masame,
and had a watering of fine straight lines.  If it was hammered on the
diagonal it was called nogi-hada or ko-masame and gave a different
watering.

Masamune and the other most celebrated sword makers (Muramasa,
Sadamune, Kane-uji, Okane-mitsu, Kane-sada, Kane-sane, Fujiwara,
Yasu-tsugu, others) took four bars as described in masame, piled them,
welded and doubled and welded 5 times, getting 4,194,304 layers in the
blade.

In all of the methods but the last two a piece of hard steel was
welded in at a point that allowed it to be made the edge when the
blade was forged into shape; in the last two, it was necessary to
increase the carbon at the edge to make it possible to harden it.
This is done by cementation, which is to pack it in charcoal and heat
it to a high temperature for a long time.  In some cases the silicon
content of the steel was increased (which western metallurgists never
succeeded in doing in that way).  Before cementing the blade was
roughly forged into shape.

I'll skip over the complex watering process.

Once the blade was forged, scraped into shape and cemented it was
painted over with a thin layer of clay and water.  This had to be
very thin near the edge but completely covering the metal.  It was
made thicker on the jigane (the parallel surfaces sloping to the
edge of the blade) and very thick on the mune and shinogi (blade
back).  The clay cover was carefully dried and then the whole is
heated to the desired temperature and the edge quenched in warm
water.

This whole process makes the edge very hard without making it
brittle, and leaves the body of the blade soft and tough.  This
is a very efficacious arrangement that Europeans never managed to
hit on, perhaps due to its complexity, and in the hands of a 
skilled smith made a bogglingly superior weapon.

Then the blade was ground and polished, and perhaps decorated.
There you have it.

IN EUROPE

Well, everyone knows about this.  Generally a homogenous bar
was tempered similarly throughout its length, giving a sharp
and brittle object or a blunt and tough one.  Pattern welding
was not in use over more than 80% of the time that Japan was
cranking out amazing swords.

Of course, swordcraft in Europe was vastly different from 
swordcraft in Japan.  Swords were in more common use, and did
not have to be especially good to be used effectively to bop
someone on their helmet.  Fighting techniques, both at the
individual level and above; armor; economics; all of these things
effected what was worthwhile to have in a sword.  In Japan,
a high-precision instrument was more effective than a glorified
club -- but it would have been a waste of time bothering with
that high-precision instrument in Europe.

WHY DID I WRITE THIS?

Actually, in terms of *DND, it doesn't matter at all.  As
I've said before, the damage system is basically completely
arbitrary anyway.  Just roll whatever dice float your boat.
Newsgroups: rec.games.frp.dnd