Tatara  　   Intro-San-inへ戻る

  

     Furnace at work during Tatara


Tatara

‘Tatara ‘ is a traditional method of steel manufacturing, the term
originally meaning ‘a bellow’.  You have only a very limited number of occasions
in a year to be able to watch the actual operation. The author is grateful to
Mr. Kageyama of The Network for History and Culture in Shimane, ‘Mokumoku’,
for giving us a chance to participate in the tour. The operation continues for three
days and nights without intermission, during which ‘Murage ‘, the project leader,
has to watch the color of the flame in the furnace and adjust the amount of charcoal
and iron sand to be added accordingly.  It is said, the color should be that of the rising
sun for the first day, that of the glaring sun of the midday in the second day, and that
of the sun set for the third day.


Murage

The Murage  we saw was a woman.  This would never have happened
in old days.  The god of metals was believed to be a woman, very envious, and no
woman was allowed in the furnace area.  The workers were all men and their wives
could not wear any makeup during the operation so as not to incur jealousy of the
goddess.  We visited the venue in the morning of the third day of operation, when
the operation was coming to a completion.  The Murage, dog-tired after a hard work
of three days and nights, with her face stained with charcoal, looked very satisfied
with the accomplishment.  She was giving orders to about ten of young workers. 
Her eyes were as vivid and fresh as the chilly air in the morning in this mountainous
area.  I was reminded of the old days when I used to do experiments for a few days
without sleep, tired but excited with the accomplishment.

This project, however, is not for the purpose of steel manufacturing. 
It does not pay.  This is for the purpose of education and exhibition.  The trainees
are college students and staff members working for some metals companies who
want to know the principle of steel manufacturing. The place we visitied was in
Yoshida Town in Shimane Prefecture, a beautiful mountainous place at about
2 hours' drive from Matsue.

                                

                                                    Riverbed stained brown


         This used to be one of the base places for steel making. The riverbed, even
now, is stained brown due to iron dust. A comprehensive literature is given in
the home page by Hitachi Metals, Ltd.,
                  (http://www.hitachi-metals.co.jp/e/tatara/ )
so only a brief summary is given here concerning Tatara.


Modern Tatara

           Tatara which was demonstrated here is modern Tatara. Ancient Tatara
dates back to more than 1000 years ago. This steel making technology is believed
to have come from some ancient Asian country, probalby India. It was improved
and refined around this area, where wood was abundant for charcoal and good
quality iron sand was available. Actually two kinds of iron sand are necessary,
'Masa iron sand' and 'Akome iron sand'. The mixing ratio of them influences the
characteristics of the produced steel.


Furnace is a vagina

             The furnace is compared to the vagina in which steel is given life.
(That's why it is Goddess rather than God who takes care of metals). The kind
of iron sand which is easily reduced and put into the furnace at the beginning
is called 'komori 'iron sand meaning 'nurse' iron sand, which is helpful in every
way in producing steel from other kinds of iron sand. The best part of produced
steel is called 'Tamahagane' and its quality is on the world top level, and used
for such sharp edges as Japanese swords. The furnace is built from soil. During
Tatara, the soil wall of the furnace is eaten up gradually in the process of reduction
and becomes so thin that it can barely sustain itself at the end of the last day.
So, it can easily be broken to take out the contents, starting from the top.
              
                                
The contents are carried out for inspection with a singly-wheeled carrier.
                               
The big residual contains such valuable metals as Tamahagane.
                          
                                          End of operation

Thus, the soil plays a big role in the chemical reaction. We can easily
understand its importance. But it is rather hard to imagine the role of
another important element, the wind.
                              

                                              The venue of tatara operation


        The big house in the middle of the photo above indicates the location
of a furnace. This place was chosen because the winds from three
directions meet there, we learned. But the most important element is,
of course, the know-how of Murage. He inherited it from his father,
who also inherited from the grandfather, and so on. Murage's responsibility
was very heavy, but he occupied the best place in residence, and earned
the highest wages.