John Baymore at River Bend Pottery

River Bend Pottery   © 1995 - 2011 All Rights reserved




The Noborigama is Born


Experimentation with the exact configuration of these split-bamboo kilns showed the potters that the shape of the chambers could make a difference in how the temperature in the chamber was regulated and also in reducing wood consumption.  As new kilns were built, the chambers slowly evolved into a more upright configuration with the curved arches following the flame flow path rather than at right angles to it.


Because the flames were moving more slowly and circuitously through the large tall chambers on their way to the chamber exit flues, they gave off more of their heat energy inside the chamber, and did so more evenly throughout the chamber.  This circulation pattern, called crossdraft, was perfected to an art by these early Asian kiln builders.


How It Works


A modern noborigama is a series of insulated crossdraft kiln chambers linked together which are running up a sloping hillside. Each chamber has flues leading into and out of it where the flames can pass through on their way up the slope to the last chamber. The sloping kiln itself creates a natural draft without the need for a really tall chimney.


At the bottom of the hillside, a large external firebox is attached to the first chamber’s inlet flues. This firebox is used mainly to bring the first chamber near to completion, and it is sized to also allow the rest of the kiln to be heated by the waste heat coming off of the first chamber firing. A large portion of the total firing time for a noborigama is used in stoking this large main firebox.


At the same time this change was taking place, the kilns tended to now be constructed half recessed into the ground, and half above the ground out of bricks made of very pure clays. These kilns resembled a piece of bamboo which was cut in half lengthwise with the nodes forming the end walls of the chambers, and were called "split-bamboo" kilns.