Japanese Sword: History Art Science

Japanese Sword:
History
Art
Science
Sword in Japanese History and Mythology
Imperial Regalia of Japan: Three Sacred Treasures
™ Sword
– Ama-no-Murakumo-no-Tsurugi or Kusanagi-no-Tsurugi
– “Sword of the Gathering Clouds of Heaven”
– “Grasscutter Sword”
– Valor
– Atsuta Shrine in Nagoya
™ Necklace – Yasakani no Magatama
– Benevolence
– Kokyo (the Imperial Palace) in Tokyo
™ Mirror
– Yata no Kagami
– Wisdom
– Grand Shrine of Ise in Mie prefecture
– "The Eight Hand Mirror"
Jade magatama necklace
from Japanese burial
Susanoo
Amaterasu
“(that which) illuminates Heaven"
“Withering Wind of Summer”
God of the sea and storms
™ Initially belong to Sun Goddess Amaterasu
– lured out of the cave with the mirror
– sword: from Susanoo as a reconciliation gift
– sword was in the tail of fire spitting serpent
™ Since 690 A.D. central part of the imperial enthronement
– no public viewing, location is unconfirmed
– no known photographs or drawings exist
– may be not originals
™ She gave the regalia to her grandson Ninigi-no-Mikoto
– sent to pacify Japan and plant rice
– ancestor of the Japanese imperial line
™ After the WWII Potsdam Declaration on July 26, 1945
– fate of the regalia was uncertain
– Emperor Showa ordered to secure regalia
– undisclosed location, protect "at all cost"
The History of Nihonto
Nanbokucho period (1336 – 1392)
™ Gokaden (Five Traditions)
– Bizen
– Soshu (Sagami)
– Yamashiro
– Yamato
– Mino
Tachi by Ichimonji.
National Treasure. TNM
Heian period (794 – 1185)
™ Improved technology
™ Horseback fighting
™ Curved blade, up to 4 ft.
™ Hung from the waist
™ Edge down: tachi
Chokuto (Ken): Ancient sword
Nara period (710 – 794)
™ Technology imported from China
™ Oldest swords ~ 400 A.D.
™ Straight blade, single cutting edge
™ Faulty tempering
Muromachi period (1392 – 1573)
Warring States period (Sengoku Jidai)
Large demand, decline in quality
Dark age of the Japanese sword
200,000 nihontō imported to China
Development of the uchigatana
– about 24 inches, worn edge up
– one hand close quarters fighting
– curve is similar to tachi
Koto: Old sword
Kamakura period (1185 – 1333)
™ Golden age of the Japanese sword
™ Retired emperor Gotoba (1180 – 1239)
– patron of the finest smiths
– forged blades himself
™ Mongol invasion attempts, 1274 & 1281
– footlong tanto, hand-to-hand combat
– wider, heavier two-hand tachi
The History of Nihonto
Imperial Japan (1912 – 1945)
™ Mass production for imperial army
™ Guntō swords: stamped, oil tempered
™ Swords making prohibited after WWII
™ “Lost generation” of swordsmiths
Edo period (1603 – 1867 )
™ Tokugawa shogunate
™ Strict class hierarchy
– samurai (shi)
– farmers (no)
– artisans (ko)
– merchants (sho)
™ Appointed “Chief Swordsmith”
– grant competency certificates
– 910 licensed smiths
1953
prohibition is lifted
Gendaito: Modern sword
Meiji Restoration (1867 – 1912)
™ Abolishing samurai class
™ 1971 – edict forcing samurai to cut top-knots
™ 1873 – creation of the Imperial Japanese Army
™ 1873 – hereditary samurai stipends terminated
™ 1876 – wearing swords is prohibited
™ Shinshinto swords
Shinto: New sword
Momoyama period (1568 – 1603)
™ Evolution of the uchigatana
– katana (24-30”) and wakizashi (18”)
™ Symbol of power and status
™ Shogunate decree for all samurai to wear daisho
™ Schools are mixed: brighter steel, flashy blades
daisho
Evolution of the Nihonto
Time
Line
Time
Line
Contemporary Sword: Shinsakuto
Nippon Bijutsu Tōken Hozon Kyōkai (NBTHK)
™ “Society for the Preservation of the Japanese Art Swords”
™ Founded in 1960
™ Strict regulations are enforced:
To register the sword with NBTHK:
– produced by licensed swordsmith
– blade over 6”, hamon, rivet hole in the tang
– less than 6”: knifes ( kogatana ), no regulation
Getting a license:
– apprenticeship under licensed swordsmith
– for a minimum of 5 years
Number of swords:
– 2 long swords (>2ft.) and 3 short swords (<2ft.) per month
– based on meticulous style of eminent smith Akihira Miyairi
All swords must be registered with the police
NBTHK Competition
– one sword per swordsmith
– 300-500 swords entered into competition
– 15 judges: swordsmiths, appraisers etc.
– 2 rounds with covered and open signature
– swords ranked first to last
– determine the value of the next year swords
– mukansa: above the competition
– ningen kokuho: living national treasure
NBTHK Tokubetsu Hozon Wakizashi from
Mutsu no Kami Fujiwara Kanenobu, a Mino smith in 17th century
Anatomy of the sword
™ “Cut well” “Not bent” “Not break”
™ Conflicting properties of steel:
– hardness: maintain sharp edge, brittle
– ductility: withstand hard blow, soft
™ Solution
– core of the soft steel, shingane
– jacket of the hard steel, kawagane
– harden only the edge, hamon
kawagane
shingane
habuchi
hamon
blade cross section
Properties of the Steel: Fe-F3C Phase Diagram
Phase diagram:
Equilibrium between the distinct material phases
Ferrite:
• α-Fe, fairly ductile
• Max. [C] solubility = 0.022%
• [C] atom ~ 2x interstitial
• Body Centered Cubic (BCC) structure
Cementite:
• Fe3C, carbide, hard and brittle, ceramic
• Orthorhombic crystalline structure
Pearlite:
• α-Fe (88%) and Fe3C (12%) composite
• Two-phase lamellar structure
Austenite:
• exist above critical (eutectoid) temp. : 727 °C
• γ-Fe : solid solution of carbon and iron
• Max. [C] solubility = 2.1% , ductile
• Face Centered Cubic (FCC) structure
Steel [C] < 2.1% ,
Cast Iron [C] > 2.1%
Martensite:
• Rapid quenching of austenite
• Traps carbon atoms, no time to diffuse out
• Body Centered Tetragonal (BCT) lattice
Cementite
Microstructure of the Iron – Iron Carbide Phases
Austenite:
• start above critical temperature: 723 °C
• carbon content: 0.83%
Pearlite:
• α-Fe / Fe3C lamellar composite
• α-Fe matrix
• Fe3C stripes
Eutectic transitions: γ-Fe --> α-Fe + Fe3C
Microstructure of the Iron – Iron Carbide Phases
Austenite:
• start above critical temperature: 727 °C
• carbon content: 0.83%
Martensite:
• metastable, kinetic phase
• not on phase diagram
• needle-shaped grains
Microstructure of the Iron – Iron Carbide Phases
Pearlite + Ferrite:
88/12 α-Fe/Fe3C + α-Fe
Pearlite: 88/12 α-Fe/Fe3C
Pearlite + Cementite:
88/12 α-Fe/Fe3C + Fe3C
Tradeoff : Ductility and Hardness
Properties and appearance of the steel:
- Location on the phase diagram
- Subsequent processing & heat treatment
Austenite:
T > 727 °C
Martensite:
annealing
quenching
[C] < 0.83%
Pearlite + Ferrite:
[C] = 0.83%
Pearlite
Hardness
Ductility
[C] > 0.83%
Pearlite + Cementite:
The Steel
Smelting :
™ Iron ore (Fe2O3) comes as a fine black sand, satetsu
™ The furnace for smelting, tatara
™ Primitive and efficient method:
– combine ore and charcoal
– pump the air trough bellows
– temperature: 1200-1500 0C
C + O 2 → CO + O ⋅
Fe 2 O 3 + CO → 2Fe + CO 2
satetsu
™ Low temperature reduction, no melting
™ Alloys with impurities are not formed, removed with the slag
™ Iron combines with carbon to form tamahagane
™ Tamahagane – “mother of metal” in kanji
Tatara and Tamahagane:
™ The Nittoho Tatara operated by NBTHK since 1977
™ Three operating cycles during the winter - 7 days / 5 people
™ Clay vessel: 1.2m (H) x 4.5m (L) x 1.5m (W)
™ 10T of satetsu and 12T of charcoal ~ 2.5T of tamahagane
™ Typical carbon content: 0.6 -1.2 % ( optimum: 1.0-1.2% )
– dense, heavy
– silvery color
– fine crystallites
tamahagane
kera
Refining the Steel: Oroshigane
™ Tamahagane - nonuniform, mixture of low and high [C] pieces
™ Outside jacket – kawagane, [C] ~ 0.7-0.8%
™ Inside core – shingane, [C] < 0.5%
™ Continuous loss of carbon during the process
™ Start forging with high carbon content, [C] ~ 1.0-1.5%
kawagane
shingane
habuchi
hamon
oroshigane
adding [C]
Fe + 3C → FeC 3
removing [C]
2FeC 3 + 3O 2 → 2Fe + 6CO
Assembling Steel for Forging: Tsumiwakashi
T (C)
700
1200
1300
1500
oroshigane, [C] ~ 1.0-1.5%
heated to 1200-15000C and
flattened into ¼ “ plates
broken into pieces and sorted
bright and clear – high [C],
kawagane
dark and muddy – low [C], shingane
plate with similar to tamahagane
composition is formed
4-5 lb. of selected pieces stacked
and wrapped in rice paper
wafers are fused at 13000C and bar
twice the length of the original
tamahagane is prepared
T(F)
1292
2192
2372
2732
Forging: Kitae – Foundation forging: Shita-gitae
make a cleft with a chisel
divide bar into two equal parts
fold the bisected bar, fuse the halves
and flatten the bar sorted
repeat the folding, remove impurities
and bubbles, homogenize
The way metal is folded will affect
jihada and jitetsu - depends on smith’s
style and school
the final block is 10” x ¾” x 1 ½ ”, divided
with chisel into three equal parts
™ Total of 6 folds: cleft, fold, hammer
™ Each fold: 30 min. / 3 heat ups
™ Each fold: 3 min. of hammering
™ Remove impurities, homogenize, air bubbles
™ Consumes ½ of the original tamahagane
Forging: Kitae – Finish forging: Age-gitae
for katana four steel pieces
are stacked an fused
another 6-7 folds
prevent oxidation with
clay and straw
™ Initial tamahagane [C] ~ 1.4%
™ 0.3% lost in shita-gitae , 0.4% in age-gitae
™ Typically another ½ of the steel lost
™ Kawagane is ready, [C] ~ 0.7%
Forming the Steel Stock: Tsukurikomi
kawagane
™ Shingane: prepare and shape – long and narrow bar
™ Folded about 10 times, drive impurities out
™ Typical shingane [C] ~ 0.2-0.5%
™ Forging temperature: 1300 0C
™ Extremely delicate and vital process
– perfect weld, no voids or gaps
– shingane completely covered by kawagane
shingane
™ Piercing tip (kissaki) is always made from the best kawagane
Kobuse-gitae
Hon-sanmai-gitae
Forming the Blank, Shaping and Rough Grinding the Blade
Sunobe:
™ Sword blank with no curve or edge
™ 10% smaller, uniform thickness
™ Define nakago and kissaki
Hizukuri:
™ Drawing the cutting edge: ha-saki
– hummer 6” at a time
– yellow (~1100 0C) and cherry red (~700 0C)
™ Require fast work and precision hammering
– overheated: separation of kawagane and shingane
– to cold: damage or fracture the sunobe
– kissaki , shinogi and mune are formed
– blade is “growing” in a straight line
– deceptively simple process
Shiage:
™ Preparation to harden the sword edge
– rough grinding and filing
– use sen to shave off irregularities
™ Use carborundum stone to rough grind the blade
™ Shape is well defined, edge is ~ 1/10”
A fully formed kissaki, shinogi,
and mune from a sunobe
Creating the Cutting Edge: Tsuchioki
™ Yakiba – hard cutting edge
™ The hardest but brittle form of steel is martensite
™ How to simultaneously:
– convert the edge to martensite
– keep the rest of the sword as ferrite + pearlite
™ Heat treatment process:
– kawagane [C] ~ 0.6-0.7% (optimum, see HRC)
– heat the blade above eutectic temperature: 723 °C
– fast cooling: austenite -> martensite
– slow cooling: austenite -> ferrite + pearlite
™ Hardness vs. carbon steel carbon content:
Sharp decrease in hardness
No gain, brittle
kawagane
shingane
Hamon:
- martensitic “blade pattern”
Habuchi:
- transitional zone
habuchi
hamon
Controlling Cooling Rate with Insulating Clay
™ Tsuchi-dori – clay mixture
™ Stick well to roughened during shiage stage surface
– clay for insulation
– charcoal powder for heating control
– sandstone (omura) to prevent cracking
– school specific ingredients
™ Thin layer on the edge, thicker towards the back
™ Control cooling rate via:
– thermal insulation
– increase surface area
™ Prevent formation of the water bubbles on the surface
™ Faster cool down with thin clay layer
™ Distribution and thickness of tsuchi-dori
– will determine hamon pattern
– hardness is the objective of the process
™ Making ashi
– literally means “foot” or “leg”
– thin tsuchi-dori strips perpendicular to the yakiba
– create pearlitic veins on hard martensitic edge
– stop crack propagation originated at the edge
Hardening the Edge: Yaki-ire
™ Yaki-ire – quenching in the cold water
Strict attentiveness followed by swift and uncompromised action
– metal is transformed and the sword is born
(zen calligrapher, strike in kendo)
– performed at night to accurately judge the temperature
– color of the steel is “like the moon in February or August”
– skill and experience – each sword is unique
™ Draw the sword through the hot coals
– slow and steady
– first edge up: 10-15 times
– then edge down: 2-5 times
™ Achieve even and uniform color
– edge: bright red or orange
– back: red or cherry red
™ Plunge the blade into the water
™ “Tale of the severed hand”
™ ½ of the swords do not survive yaki-ire
™ Yaki-modoshi – tempering at 160 0C
– reheating and quenching again
– relieve the stress, break down martensite crystals
The Science: Yaki-ire
™ Heat treatment
– heating to a high temperature
– holding at temperature
– cooling down at a specific rate
CCT diagram for hypoeutectoid steel [C] < 0.8%
Circles – DPH ( diamond-pyramid hardness )
™ Continuous cooling transform. (CCT) diagram
– follow cooling curves
– from the top left to bottom right
– steel and sample specific
a – austenite
f – ferrite
p – pearlite
b – bainite
m – martensite
Fast
(~10sec): austenite –> martensite
Medium (~1min): austenite –> mixture
Slow
(~3min): austenite –> ferrite:pearalite
™ Steel cracking is the problems during quenching
– high rate of cooling: surface cooler than interior
– surface forms martensite before the interior
– constrains from outer martensitic layer leading to residual stresses
Heat Transfer Modeling: Yaki-ire
Prifile of
yakiba-tsuchi
Measured heat transfer coefficient
Temperature distribution during yaki-ire
0
1
800 - 400 0C:heat transfer coefficient with thin clay
is higher than that of without any clay
Nucleation boiling:
– rapid, explosive, formation of bubbles
– strong local velocity within the liquid film
– increases heat transfer
– surface dependant
Film boiling:
– continuous layer of vapor covers the surface
– insulating effect of the vapor
– reduced the rate of heat transfer
– Leidenfrost effect
Thin clay – nucleation boiling
Thick clay – film boiling
Bare metal – film boiling
Inoue Tatsuo, Mat. Sci. Res. Int. Vol.3, No.4 pp. 193-203 1997
s
e
c
o
n
d
s
2
3
4
5
10
Temperature, 0C
gyaku-sori: reverse bending ~ 1s
sori : normal bending ~ 10s
Heat Transfer Modeling: Yaki-ire
Longitudinal stress distribution and residual stresses
Simulation of quenching with
different tsuchi distribution
(a)
1
tsuchi: uniform 0.8 mm
(b)
s
e
c
o
n
d
s
2
tsuchi: uniform 0.1 mm
(c)
4
0.8 mm on the back
0.1 mm on the edge
10
volume fractions of martensite %
Stress σ, MPa
Inoue Tatsuo, Mat. Sci. Res. Int. Vol.3, No.4 pp. 193-203 1997
Significant stress in yakiba
Fracture stress 1600-1700
MPa
yaki-modoshi
Adjusting the Curvature: Sorinaoshi
™ Sunobe is almost straight before quenching
™ During yaki-ire curvature is increased by almost ½”
™ Volume change between austenite and martensite
™ Adjusting the curve
– straightening by hammering
– heating on copper block and quenching
– addjust sori locally
Martensitic transformation:
• No long range diffusion
• No compositional change
• Transformation occurs by shear
• Austenite to Martensite → 4.3% volume increase
γ ( FCC )
0.8 %C
⎯Quench
⎯⎯→
α ' ( BCT )
0.8 %C
Two FCC unit cells:
- contract by 20% in the z direction
- expand by 12% along the x and y directions
(111)γ <=> (011)α’
[101]γ <=> [111]α’
[110]γ <=> [100]α’
[112]γ <=> [011]α’
Bain model – structural transformation with a minimum of atomic motion
One-to-one correspondence between γ and α’ atoms
Just a Beginning….
™ Kajitogi : rough polishing
™ Hi : decorative grooves ( add surface area! )
™ Horimono : decorative carvings ( tatoo )
™ Nakago : the tang, filed, never cleaned
™ Mekugiana : the rivet hole
™ Mei : the signature, testing, owner etc.
– engraved in the very end
– often forged or destroyed
– “legend of Kanemitsu”
™ Polishing: the art by itself
– put a sharp edge
– reveling the hamon, jihada, jitetsu
– bring the sword to life
™ Habaki: blade is floating in the scabbard (saya)
™ Shirasaya – simple “white scabbard”
– ho tree (magnolia obovata)
– glued with sokui, paste from cooked rice
– carved with shallow lip for the edge
™ Saya
– kurigata
– kojiri
– sageo
– koiguchi
Fully Mounted Sword: Koshirae
™ Tsuba
– habaki
– seppa
™ Tsuka
– fuchi / kashira
– makishitasame
– tsukaito
– menuki
Shinto katana. 1600’s. Signed – Suruga no Kami Kunimasa. Yasusada School. Soshu style. Notare
hamon. The mounts are original to the blade. Fuchi kashira done in shakudo and gold with a floral
design. The tsuba is a large iron sukashi with a design of ginger leaves.
http://www.ricecracker.com/
What Makes Katana a Superior Sword?
™ Forging
– optimal [C] content
– folding process
oroshigane
™ Design
– kawagane jacket
– shingane core
– hamon
volume fractions of
martensite %
™ Heat treatment
– controlled quenching
– martensitic edge
Hagakure
A certain swordsman in his declining years said the following:
In one's life there are levels in the pursuit of study. In the lowest level, a person studies but
nothing comes of it, and he feels that both he and others are unskillful. At this point he is
worthless. In the middle level he is still useless but is aware of his own insufficiencies and
can also see the insufficiencies of others. In a higher level he has pride concerning his own
ability, rejoices in praise from others, and laments the lack of ability in his fellows. This man
has worth. In the highest level a man has the look of knowing nothing.
These are the levels in general. But there is one transcending level, and this is the most
excellent of all. This person is aware of the endlessness of entering deeply into a certain
Way arid never thinks of himself as having finished. He truly knows his own insufficiencies
and never in his whole life thinks that he has succeeded. He has no thoughts of pride but
with self-abasement knows the Way to the end.
It is said that Master Yagyu once remarked:
"I do not know the way to defeat others, but the way to defeat myself. ''
Throughout your life advance daily, becoming more skillful than yesterday, more skillful than
today. This is never-ending.
Extra
The Science: Yaki-modoshi
™ Tempering
– heating below eutectoid temperature
– holding at temperature followed by cooling
™ Cold work: mechanical deformation of at relatively low temperatures
– increase point defect and dislocations
– stronger material
Tempered Martensite
Martensite
α′(Fe) ⎯tempering
⎯⎯
⎯→ α (Fe) + Fe3C
T<TE
Pearlite
≠ α (Fe) + Fe3C
™ Tempered martensite:
– distribution of fine particles of Fe3C in α matrix
– hardness more than pearlite, ductility more than martensite
– hardness and ductility controlled by tempering temperature and time
Fe-C diagram:
• austenite: FCC γ-Fe ductile
• ferrite: BCC α-Fe fairly ductile
• FCC unit cell > BCC unit cell
• cementite: 2nd phase [Fe3C] brittle
• cementite: [C] is in excess of the solubility limit
• pearlite: two-phase lamellar structure
• pearlite: α-Fe (88%) and Fe3C (12%) whiskers
Eutectic transitions:
• Cementite: γ-Fe --> α-Fe + Fe3C
• Ledeburite: L --> γ-Fe + Fe3C
Fe-Fe3C
Martensite:
• tetragonal lattice
• rapid quenching of austenite. change in volume
• traps carbon atoms, no time to diffuse out
Heat Treatment
holding
heati
ng
T
AT
Q
T
A
N
time
Annealing
Furnace cooling
RC 15
Coarse pearlite
Quenching
Water cooling
RC 65
Martensite
Tempering
Heating after quench
RC 55
Tempered martensite
Normalizing
Air cooling
RC 30
Fine pearlite
Austempering
Quench to an intermediate
temperature and hold
RC 45
Bainite
Continuous Cooling Transformation Diagram for Eutectoid Steel
Cooling curves
Constant rate
800
Coarse peralite
723
a
rm
No
h
in g
li z
400
P
n
ue
lq
Oi
300
ch
200
Martensite:
100
M+ P
M
0.1
eal
nn
ll a
Fu
500
enc
Water qu
Austenite
T( 0K) →
600
1
10
102
t (s) →
Fine peralite
Coarse P
Fine P
103
104
105
Time Temperature Transformation Diagram for Eutectoid Steel
™ Formation of bainite – austempering
™ Bainite: short needles of Fe3C in plates of ferrite
™ Less strong but more ductile than martensite
Austenite
Bainite
Upper bainite:
Austempering
Martempering
Lower bainite:
References
Front Picture: Blacksmith Munechika (end of the 10th century), helped by a fox spirit,
forging the blade kogitsune-maru ("Little fox"). Engraving by Ogata Gekkō (1859–1920), 1873.
“Materials Science and Engineering: An Introduction” , 6th Edition William D. Callister, Jr., Univ. of Utah
“Phase Transformations in Metals and Alloys” David Porter & Kenneth Esterling Van Nostrand Reinhold Co. Ltd., New York (1981)
“The Samurai Sword: A Handbook” Yumoto, John M. Tuttle Publishing, 2002
“The Craft of the Japanese Sword” by Leon and Hiroko Kapp and Yshindo Hoshihara; Kodansha America, Inc; 1987
“THE JAPANESE SWORD : The Material, Manufacturing and Computer Simulation of Quenching Process”
Inoue Tatsuo, Material Science Research International Vol.3, No.4 pp. 193-203 1997
“The Forging of a Japanese Katana” Michael Morimoto Colorado School of Mines June 14th, 2004
“Samurai: The weapons and spirit of the Japanese warrior” by Clive Sinclaire; First Lyons Press; 2001
“The Japanese Sword: The Soul of the Samurai” by Gregory Irvine; Weather Hill Inc; 2000
“The Arts of the Japanese Sword” by Basil W. Robinson; Charles E. Tuttle Company; 1971
“The Japanese Sword” by Kanzan Sato and Joe Earle; Kondansha International Ltd. And Shibundo; 1983
http://web.iitd.ac.in/~rajesh/
http://www.engr.usask.ca/classes/ME/324/Class-notes/Lecture3-Week11-2005.doc
http://yakiba.com/
http://legacyswords.com/fs_gen_sword6.htm
http://www007.upp.so-net.ne.jp/m-kenji/asj_lecture.htm
http://www.tnm.jp
http://www.samuraisword.com/nihontodisplay/CUTTING_TEST/Munehiro/index.htm
http://www.ksky.ne.jp/
http://www.thejapanesesword.com/
http://www.shibuiswords.com/
http://zenkou.com/books.asp/
http://www.arscives.com/bladesign/mino_uchigatana.htm
http://www.geocities.com/alchemyst/terms/terms.htm
http://www.nihontoantiques.com/jigane_and_jihada.htm
http://www.arscives.com/historysteel/japaneseintroduction.htm
http://www.youtube.com/watch?v=xzJAUKZGyNQ&feature=related
http://en.wikipedia.org/wiki/Japanese_sword
The Beauty of the Sword
“Cut well” “Not bent” “Not break”
The appearance is purely a side effect
Jihada and Jitetsu
Foundation forging: Shita-gitae
™ Ji – blade surface above hamon
™ Hada – “grain” pattern
™ Tetsu – “iron” color, texture, quality
™ High temperature – metal pastry dough
™ 13-16k layers per inch (214 = 16,384)
Basic Jihada:
Itame:
– wood grain, fold alternatively
– intermixing of the layers
Masame:
– straight grain pattern, fold in one direction
– remnants of the original tamahagane wafers
Mokume:
– itame with 'whorls’
Ayasugi:
– regular wave lines
– selectively file away masame pattern
masame
itame
Nashiji Hada:
–”pear skin” dense form of komokume
Konuka Hada (Hizen):
–”rice bran” coarse form of nashiji
Muji Hada:
–”plain” “unfigured” very tight and small
itame
masame
mokume
ayasugi
Jihada
Ko-itame
itame
muji
Ô-itame
ayasugi
itame
itame-nagare
chû = medium
Ko = small
Ô-mokume
Ô-mokume
Ô = large
Hamon
Osafune Yukisada. Tachi blade. 1376.
choji
Magoroku Kanemoto. circa 1450.
“… value rating of 100 pieces of gold."
sanbonsugi
™ Yakiba – the line of the hardened edge
™ Takes on white color when skillfully polished
™ More than 130 documented types of hamon
Kozaemon Yukihira. 1998.
Mukansa rank by NBTHK.
martensite
gunome/notare
Utsuri
™ Utsuri – reflection, print, impression
™ Misty white shadow above the hamon
™ Typical to Bizen blades, very difficult to produce
™ Bright cloudy areas of pearlite + ferrite
Irregular pattern relating
with the choji pattern hamon
Pearlite + Ferrite:
™ Mune is below eutectic temp.
™ Narrow temperature tolerance
™ Uniform temperature gradient
Nie and Nioi
Hada
Martensitic crystals embedded in pearlitic matrix
Mune
nioi → konie → nie → aranie
(smallest) (small) (large) (rough)
Hamon
™ Nioi – vapor, white and misty
™ Not visible to the eye
™ Lower quenching temperature
NIOI
NIE
™ Nie – resemble stars in the night sky
™ Visible to the eye, large martensite grains
™ Longer at higher temperature
™ Perfected by Masamune
“Activities” or “Workings” on the Blade: Hataraki
™ Bright martensitic streaks in high carbon areas
Kinsuji – “golden lines” parallel to the blade edge
Inazuma – “lightning bolt” zigzag or perpendicular to the blade
kinsuji
™ Large ferrite conglomerates on the tempered steel
™ Different from martensitic particles on the hamon
™ Not the same as jihada, free from layer pattern
jinie → chikei
→ jifu
(fine) (curved lines) (islands)
inazuma
Bugei Tameshigiri - James Williams
Shizan by Nakamura Sensei (Ningen Kokuho)
Shito
Extra
Tameshigiri
™ Tameshigiri: the purpose of cutting ( “test-cutting” )
– closely related to criminal justice in Edo period
– public execution ritual
– test cutting of convicted felons to evaluate the quality of swords
™ Suemonogiri: the object/target to be cut ( “fixed (non-living) object cutting” )
– specific form of tameshigiri (typically corpse as stationary target)
– skills and abilities of the swordsmen
™ Until early 1700’s:
- very popular amongst higher ranking samurai
- even Daimyo lords engaged in tameshi on
corpses by themselves
™ Mid 1700’s:
- otameshi-geisha - professional sword testers
- suemono-shi - lower ranking samurai with
recognized swordsmanship skills
™ Late 1700’s:
- Yamada family monopolized tameshi
commissions from the Shogunate
- Monopoly lasted for 8th generation
until Meiji Restoration
- The family remained ronin in official record
™ The swords were rated as:
Saijo O-wazamono - best cutting swords
O-wazamono - excellent cutting swords
Ryo-wazamono - very good cutting swords
Wazamono - good cutting swords
™ Modern tameshigiri can be divided into two categories
Shi-zan - test of the swordsman’s skills by cutting
maki-wara, tatami-omote, and bamboo.
Shi-to - test of the quality of the blades through the
use of harder cutting media
S. Takeuchi, Ph.D. Department of Sociology University of North Alabama 2003
Tameshigiri
Shinshinto katana. 1865. Signed by Munihiro.
Ryokuruma cut performed by Goto Shintaro
in execution of a criminal
The Legend of Masamune and Muramasa
A legend tells of a test where Muramasa challenged his master,
Masamune, to see who could make a finer sword. They both worked
tirelessly and eventually, when both swords were finished, they decided
to test the results.
The contest was for each to suspend the blades in a small creek with the
cutting edge facing the current. Muramasa's sword, the Juuchi Fuyu
(10,000 Winters) cut everything that passed its way; fish, leaves floating
down the river, the very air which blew on it. Highly impressed with his
pupil's work, Masamune lowered his sword, the Yawaraka-Te (Tender
Hands), into the current and waited patiently. Not a leaf was cut, the fish
swam right up to it, and the air hissed as it gently blew by the blade. After
a while, Muramasa began to scoff at his master for his apparent lack of
skill in the making of his sword. Smiling to himself, Masamune pulled up
his sw ord, dried it, and sheathed it. All the while, Muramasa
was heckling him for his sword's inability to cut anything.
A monk, who had been watching the whole ordeal, walked over and
bowed low to the two sword masters. He then began to explain what he
had seen. "The first of the swords was by all accounts a fine sword,
however it is a blood thirsty, evil blade as it doesn't discriminate as to
who or what it will cut. It may just as well be cutting down butterflies as
severing heads. The second was by far the finer of the two, as it doesn't
needlessly cut that which is innocent and undeserving."
Masamune vs. Muramasa
Masamune Okazaki, also known as Goro Nyudo Masamune (Priest Goro
Masamune) is widely recognized as Japan's greatest swordsmith. As no exact
dates are known for Masamune's life, he is believed to have worked in Sagami
Province during the last part of the Kamakura Era (1288 - 1328)
Muramasa Sengo
The founder of the school of sword-making at Ise province. The
earliest known work of the school is dated at 1501; the Muramasa
school continued into the late 1500's during Muromachi Era.
The swords of Masamune have a reputation for superior beauty and quality,
remarkable in a period where the steel necessary for swords was often impure.
He is considered to have brought the art of 'nie' to its perfection.
Muramasa's swords fell out of favor with the Japanese government
when Tokugawa Ieyasu became shogun. It is said that Ieyasu had
lost many friends and relatives to Muramasa blades and had cut
himself badly with one, so he forbade his samurai to wear blades
made by Muramasa. Since opponents of the Tokugawa Shoguns
would often wish to acquire Muramasa blades, forgeries of
Muramasa blades were also often made.
Perhaps the best known Masamune sword is Honjo Masamune, a symbol of the
Tokugawa shogunate and passed down from one shogun to another.
Signed works of Masamune are rare. The examples "Fudo Masamune",
"Kyogoku Masamune", and "Daikoku Masamune" are accepted as his genuine
works. His swords are the most frequently cited among those listed in the
Kyôho Meibutsu Cho, a catalogue of excellent swords in the collections of
daimyos edited by the Hon'ami family of sword appraisers and polishers.
An award for swordsmiths exists called the Masamune prize which is awarded
at the Japanese Sword Making Competition. Although not awarded every year it
is presented to a swordsmith who has created an exceptional work.
Due to the stigma attached to them, many Muramasa blades had
their signature changed or removed. It has also been told that once
drawn, a Muramasa blade has to draw blood before it can be
returned to its scabbard, even to the point of forcing its wielder to
wound himself or commit suicide. Thus, it is thought of as a
demonic cursed blade that creates bloodlust in those who wield it.
Legend of Amakuni
Amakuni (天國) is the legendary swordsmith who created the first single-edged
longsword with curvature along the edge in the Yamato Province around 700 AD. He
was the head of a group of swordsmiths employed by the Emperor of Japan to make
weapons for his warriors. His son, Amakura, was the successor to his work. Although
there are almost no modern examples of signed works by Amakuni, legend has it that
the double-edged katana, Kogarasu Maru, was forged by this man. The true author of
this work is not known, though the work bears similarities to works of the various
Yamato schools so it is thought to be an early example of work from this province.
The Legend
One day, Amakuni and his son, Amakura, were standing in the doorway of
their shop, watching the Emperor's warriors return from battle. Although having
done so on previous occasions, the Emperor did not give Amakuni any sign of
recognition. Having always looked upon these gestures as a sign of appreciation
for his efforts and hard work, Amakuni suddenly noticed that nearly half of the
returning warriors were carrying broken swords. Determined to make things right,
Amakuni and Amakura went about gathering remnants of the swords and examined
them. It appeared that the chief reasons for breakage were that the swords had
been improperly forged and that the soldiers had struck hard objects, probably
armor or other weapons, with them. Once again, the Emperor's subtle yet audible
rebuff ran through his mind. Tears filled Amakuni's eyes, and he said to himself,
"If they are going to use our swords for such slashing, I shall make one that will
not break.“ With this vow, Amakuni and his son sealed themselves away in the
forge and prayed for seven days and seven nights to the Shinto gods. Amakuni
then selected the best iron sand ore he could obtain and refined it into steel.
Working without rest, the two worked at their apparently impossible task.
Thirty days later, Amakuni and his son emerged gaunt and weary from the
forge with a single-edged sword with curvature.
Undaunted by the other swordsmiths, who believed them to be insane, Amakuni and Amakura ground and polished the new sword. During the
following months, Amakuni and his son continued with their work, forging many types of improved swords. In the following spring, there was
another war. Again the samurai returned, and as they passed by, he counted over thirty-one swords with perfect, intact blades. As the Emperor
passed, he smiled and said, "You are an expert swordmaker. None of the swords you have made failed in this battle." Amakuni rejoiced and
once more felt that life was full and joyous. No one knows when Amakuni died.
The Samurai Sword: A Handbook. Yumoto, John M. Tuttle Publishing, 2002
Legend of Kanemitsu
Bizen Kanemitsu
He was undoubtedly amongst the foremost makers of his day, and that ever lived. It is recorded
that he was born in "ko-an" 1278 and died in "en-bun" 1356 at the age of 83. At the age of 42
Kanemitsu was invited to study with Masamune, the most famous sword maker of his day. Later
on his popularity nearly equaled that of Masamune, especially in his native Bizen province.
Kanemitsu swords were well known for there exceptional beauty, and functionally. His swords
are considered to be the sharpest swords ever known. They were also the subject of much
folklore.
“Kabutowari“ - the helmet cutter
“Ishikiri" - the stone cutter
“Teppo kiri" - the gun cutter
One story sights an incident when during the course of a battle a samurai was cut with a
Kanemitsu blade. The cut was so clean, and painless that the man swam across a river in
retreat. When he attempted to climb from the water, his body fell to the shore in two half's.
The Legend
One day Kanemitsu was enjoying a moment of rest in his shop. He suddenly found
himself listening intently to the sound of the chisel of his neighbor in the shop nest door.
Angrily he arose, dashed nest door, and seized the sword on which the other smith had
been chiseling the name. “You were putting my name on that sword” said Kanemitsu.
The other smith admitted that he had been doing so and apologized.
“How did you know?” the guilty one asked. ”Were you watching?”
“No,” answered Kanemitsu, “but I was listening. You used a greater number of strokes
that was necessary if you had been writing your own name”
The Samurai Sword: A Handbook. Yumoto, John M. Tuttle Publishing, 2002
http://www.samuraisword.com/nihontodisplay/Hozon/Nobushige/index.htm
References
Front Picture: Blacksmith Munechika (end of the 10th century), helped by a fox spirit,
forging the blade kogitsune-maru ("Little fox"). Engraving by Ogata Gekkō (1859–1920), 1873.
“Materials Science and Engineering: An Introduction” , 6th Edition William D. Callister, Jr., Univ. of Utah
“Phase Transformations in Metals and Alloys” David Porter & Kenneth Esterling Van Nostrand Reinhold Co. Ltd., New York (1981)
“The Samurai Sword: A Handbook” Yumoto, John M. Tuttle Publishing, 2002
“The Craft of the Japanese Sword” by Leon and Hiroko Kapp and Yshindo Hoshihara; Kodansha America, Inc; 1987
“THE JAPANESE SWORD : The Material, Manufacturing and Computer Simulation of Quenching Process”
Inoue Tatsuo, Material Science Research International Vol.3, No.4 pp. 193-203 1997
“The Forging of a Japanese Katana” Michael Morimoto Colorado School of Mines June 14th, 2004
“Samurai: The weapons and spirit of the Japanese warrior” by Clive Sinclaire; First Lyons Press; 2001
“The Japanese Sword: The Soul of the Samurai” by Gregory Irvine; Weather Hill Inc; 2000
“The Arts of the Japanese Sword” by Basil W. Robinson; Charles E. Tuttle Company; 1971
“The Japanese Sword” by Kanzan Sato and Joe Earle; Kondansha International Ltd. And Shibundo; 1983
http://web.iitd.ac.in/~rajesh/
http://www.engr.usask.ca/classes/ME/324/Class-notes/Lecture3-Week11-2005.doc
http://yakiba.com/
http://legacyswords.com/fs_gen_sword6.htm
http://www007.upp.so-net.ne.jp/m-kenji/asj_lecture.htm
http://www.tnm.jp
http://www.samuraisword.com/nihontodisplay/CUTTING_TEST/Munehiro/index.htm
http://www.ksky.ne.jp/
http://www.thejapanesesword.com/
http://www.shibuiswords.com/
http://zenkou.com/books.asp/
http://www.arscives.com/bladesign/mino_uchigatana.htm
http://www.geocities.com/alchemyst/terms/terms.htm
http://www.nihontoantiques.com/jigane_and_jihada.htm
http://www.youtube.com/watch?v=xzJAUKZGyNQ&feature=related
http://en.wikipedia.org/wiki/Japanese_sword