復元古窯の焼成実験(II) : 藁を燃料とした野焼き

Abstract

Noyaki firing method was probably used in Japan from the Johmon period to the Kamakura period. (BC75-AD14) We made two experiments. During the first one we laid straw down and put the green ware on top of it, then we packed straw into the green ware and laid a thick layer of straw (approximately 1m) over it. We controlled the temperature of the fire using rice hull and rice hull ash. During the second experiment we controlled the temperature using a firebrick wall and rice hull. Experimental results are summerized as follows; (1) Straw lightness makes it a good firing material when stacking, and straw ash even when half burned didn't crack the green ware as half burned wood would. (2) During the first experiment we could hold the average temperature at about 500℃ by controlling the amount of rice hull and rice hull ash put over the straw. The temperature peaked at about 850℃. During the second experiment the average temperature was held at about 700℃. The temperature's peak was about 900℃. (3) The temperature of the second experiment kept longer because of the wall. (4) Earthenware fired light brown using straw. (5) We made sure that the straw burned compretely, so the ware didn't turn black. (6) We put some of earthenware into a protective box packed with sawdust or pineneedles and sealed them as well as we could. The result was that ware turned black.