marz12aug

１．日立金属公式ホームページhttp://www.hitachi-metals.co.jp/tatara/nnp020603.htm
↑compositional formula of "MASA"(Satetsu of Tamahagane)

I wrote down a homepage of "Hitachi-Metal.co" in my profile. 
Chemical composition of Masa is mentioned in there. Masa includes iron content of 59%. This equals high-quality iron ore.

2.日本各地の砂鉄の成分
http://www.geocities.jp/e_kamasai/kanren/kan2-6-D.html
↑The ingredient of the "Satetsu" of all parts of Japan 
3.Telescorp Pictuer of Satetsu
http://www.wakou-museum.gr.jp/spot7.htm

4.The Japanese arrowhead penetrated even a frying pan http://www.tamagawa.ac.jp/sisetu/kyouken/kamakura/kyuba.html
video:
http://blogs.yahoo.co.jp/kuroken3147/53572171.html/

5."""
6.ABOUT Tosei-Gusoku(16c japanese armor)
http://www.rakuten.ne.jp/gold/yoroi/Q&A.html
7."Samurai-bow(YUMI)vsEngland Longbow
http://vodpod.com/watch/2171187--samurai-bow
8.  AD5C japanese-plate-armor http://ameblo.jp/goodfield/entry-10312106364.html
http://www.hyogo-c.ed.jp/~maibun-bo/iseki39.htm
http://image.space.rakuten.co.jp/lg01/75/0000141975/21/imgd9727275ghpo4s.jpeg
NEW：
9.Akagawa-Odoshi-yoroi(12th centry armor) National treasure of japan.
http://www.pref.okayama.jp/kyoiku/kenhaku/yomimono/akagawa/index.html
NEW:10:"Mouko-syuurai-Ekotoba蒙古襲来絵詞"
http://upload.wikimedia.org/wikipedia/commons/3/31/Takezaki_suenaga_ekotoba_1-2.jpg
When we compared only one material,modern steel surely looks like more high quality than Tamahagane. 
However, Katana is art of the steel which put several kinds of steel together synergistically.
the swordsmith of Katana uses many method with exquisite balance. As a result, "the impurities" of Tamahagane become "the potentiator" making up for strength. 
Tamahagane can reduce to elements at low temperature. 
The particle of steel refined at a high temperature grows too much up bigger. In other words the steel needing a high temperature becomes fragile. 
but Tamahagane's particle is small and sharp.
This particle like a needle is strong.
We can confirm these by an electron microscope. 
In addition, such a characteristic of Tamahagane is useful for Strong combination of low carbon steel with high carbon steel.