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<FONT face="Verdana,Arial" color="#009933">SWORD BLADE NIKU by Keith
Larman <BR>June 2000 </FONT></P>
<P><FONT face="Verdana,Arial" size=-1 color="#009933"><BR> The following
article was written in response to a series of questions on an on-line forum on
the topics of niku, blade widths, different tsurikomi (blade structure), and the
effects of those things on the efficiency of tameshigiri practice. The post was
originally written with the idea of illustrating niku in very simple terms, but
ended up being more a long article on the complexity of the issue. I had hoped
to help those looking to buy swords for tameshigiri to better understand the
role of niku but also to help them understand it"s raison d-etre historically.
But it grew in length as well as scope. Niku is a topic that I"ve thought about
a lot as a user, a collector, and mostly lately as a guy struggling with
understanding traditional polishing (I work predominantly on modern blades made
by Western smiths working in the Japanese style). I don"t profess to have all
the answers. I don"t even claim that I hold all these views with certainty. I"m
walking down the same road as everyone else. So take it all with the spirit that
some things could be starting points for new discussions. </FONT></P>
<P align=center><FONT face="Verdana,Arial" color="#009933">
Understanding Niku </FONT></P>
<P align=left><FONT face="Verdana,Arial" size=-1 color="#009933">Niku
literally translates into "meat". It"s a term used to describe the tendency of a
traditional Japanese blade to have a bulging cross section on the side surface.
Another way to think about niku is the degree of "roundness" of the ji surface.
Niku is distinct from thickness of a blade, or the kasane. A thick blade with a
flat ji surface has no niku. A blade could be vastly thinner and lighter but if
it has a lot of roundness to the ji it will have niku. So you have to separate
niku from kasane. </FONT></P>
<P align=center><FONT face="Verdana,Arial"color="#009933">Traditions
</FONT></P>
<P align=left><FONT face="Verdana,Arial" color="#009933">Depending on the era, katana were often made with considerable niku. A
common method for determining the amount a blade has been polished in its
lifetime is to look at the amount of niku. If the blade is "hiraniku ari", or
with a lot of niku, it"s probably not been polished a whole lot or else the
polishers were extremely careful to preserve the blade. If the surface of a
blade that started out life with considerable niku is flat, well, it"s either
been polished a lot or been polished by someone along the way who didn"t take
the time nor care to preserve the niku. Consider the following drawing (Figure
1). The solid lines show the blade when first made and polished. The dashed
lines show what happens to the ji surface over time. (Obviously all surfaces
will be reduced during repeated polishing, but I only wanted to illustrate the
effect on niku.) </FONT>
<center><img src="http://www.isword.co.kr/img/figure1.gif"></center>
<P align=left><FONT face="Verdana, Arial, Helvetica, sans-serif" size=-1 color="#009933">What
you will see is a gradual flattening of the ji surface. This is inevitable as
the polisher normally will be concerned with preserving the edge material as
much as is possible. So if material has to be removed due to chips or rust,
generally it has to be removed all over the blade, but it"s better to sacrifice
bits of the side over losing hard edge. And no matter how good you are, given
enough time it will simply get flatter. There"s only so much you can to without
turning the sword into a toothpick! </FONT></P>
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