TV Program Description
Original PBS Broadcast Date: October 9, 2007
English archers had their longbows, Old West sheriffs had
their six-guns, but samurai warriors had the most fearsome
weapon of all: the razor-sharp, unsurpassed technology of the
katana, or samurai sword. In this program, NOVA probes
the centuries-old secrets that went into forging what many
consider the perfect blade.
The beauty and lethality of the curved steel blade became
identified with the distinctive culture of those who wielded
it so expertly: the samurai warriors of medieval Japan,
celebrated in countless Japanese woodcuts, prints, and films.
Fifteen traditional Japanese craftsmen spent nearly six months
creating the sword that NOVA follows through production, from
smelting the ore to forging the steel to sharpening the blade
to a keen edge, capable of slicing through a row of warriors
at one swoop—although NOVA does not put the super-weapon
to this ultimate test. (See a
slide show of the
process.)
Not that samurai sword fighting has died out—far from
it. The program also traces the schooling of a modern-day
devotee of samurai combat: Midori Tanaka, a receptionist for a
Japanese electronics firm by day and a blade buff by night.
For Tanaka it's a family tradition, since her father, Fumon
Tanaka, is a grand master swordsman.
Father and daughter show their mutual respect with a
breathtaking test of skill. Midori draws a bow, aiming an
arrow directly at her father's heart. His only protection is
his sword. When she releases the string, he slices the
speeding arrow in half, inches from its target.
Japanese sword-making developed centuries ago, before electron
microscopy, mass spectrometry, and other tools of modern
materials analysis enabled scientists to understand exactly
why the swords are as good as they are. Professor Michael
Notis of Lehigh University, an expert on samurai swords, sheds
light on the principles that underlie the weapons' strength,
resilience, beauty, and distinctive shape. (See an
interview on
metal's properties with Notis's colleague Rick Vinci.)
For example, during smelting, iron-ore sand is heated with
charcoal, which provides a source of carbon that alloys with
the iron to create steel. Ancient craftsmen deliberately
stopped just short of a uniform liquid state for the white-hot
steel, which resulted in a product with varying amounts of
carbon throughout. The harder high-carbon steel was forged
into the sword's edge, which had to be hard and sharp, while
the more resilient low-carbon steel was used as the core of
the weapon to produce a blade resistant to breaking during
combat.
This sandwich of two different types of steel contracted at
different rates during rapid cooling, or quenching, which
caused the blade to warp lengthwise, giving it its distinctive
curve that proved so deadly when wielded in a slashing arc.
"The unique aspect of the Japanese sword is that the craftsmen
were able to put the right materials in the right place to get
optimum properties for the entire object," Notis tells NOVA.
Without access to the insights of modern science, Japanese
craftsmen a millennium ago worked out an exacting method that
is still followed by a devoted few and that produces the
Stradivarius of swords.
Program Transcript
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