All the ceramic products made by using fuelwood as fuel can be called firewood. The works can be divided into two categories: glazed (bottom glaze) and unglazed (natural glaze). For example, Temmoku tea bowl and celadon glaze of the Song Dynasty are both glazed, while the Japanese pre-burning is unglazed (taking the effect of natural ashing). Wood burning is an ancient art, and kiln firing is very difficult. The success or failure of woodburning works depends on the relationship between earth, fire, wood, and kiln.

Soil: there are many clay soils for wood burning, which are prepared by the potter himself. The heat-resistant temperature of the clay, the properties of the firewood kiln, and the types of firewood are taken into consideration. The pursuit is to let the soil can produce a warm, honest, calm, and introspect beauty of wood-burning.

Wood: generally, wood needs to be left standing for more than three to six months (avoid too wet) to facilitate combustion. Its types include camphor, longan, litchi, lotus and waste wood, etc.
Kiln: it only burns wood to provide heat energy. Generally, it takes three to five days for the kiln to burn wood, during which the wood needs to be cast in shifts without sleep. The speed and way of adding wood, the total type of firewood, weather conditions, airflow, and other subtle factors are constantly affecting the color and luster changes of kiln works.

Ash: When the pottery is burned in the chai kiln, the ashes that are completely burned are extremely light and drift away with the heat stream. When the temperature is higher than 1200℃, wood ash begins to melt, and the iron in wood ash makes the iron in the damaged pottery form glaze, presenting different color changes. The glaze formed in this way is called “natural ash glaze”. The natural ash glaze is not eye-catching at first glance, but the more you look at it, the more durable it is, which is the charm of the wood-burning works.