As the exact proportions of these anagama evolved through repeated firings and experimentation
on the part of the potters, they eventually were able to achieve rather high temperatures.
This was typically achieved through excessively long duration firings and the consumption
of huge amounts of wood fuel. These early single chamber kilns fired very unevenly,
and many pots either had to be refired becasue they were too cold, or were ruined
because they got too hot. The firings were often a communal project involving whole
villages. A firing was a major undertaking, and was costly in terms of human resources,
firewood, and in badly fired pots.
The Anagama Improves
In seeking to make more and better pots, and therefore have better lives for themselves,
potters experimented with how to improve the firings of their anagama kilns. For
most of them, a potter's life teetered on the edge of hand-to-mouth survival, and
any economic competitive edge was welcomed.
They found that if they created temporary segments within the single large chamber
by piling up solid walls of saggars (early kiln furniture) and allowing small flues
between them for the passage of the flames, they could even out the temperature in
the chamber somewhat. They then also made small openings from the outside ground
level through which they could drop firewood into each of these segmented areas.
It was a small technical step from this discovery to the construction of permanent
segments within the anagama-type structure with permanent stoke holes along the sides
of the chamber. Clay pillars were placed inside to create numerous distinct chambers
with flues leading out of one and into the next..
Once these primitive kilns had been fired, a "skin" of fired hard clay formed on
the inside surface making the kiln structures somewhat permanent. Each firing made
it more durable. As you might imagine, building such a kiln in the first place in
the soft clay was a hazardous occupation, with collapse of the soft ground always