Exchange with peoples of the southern Korean peninsula led to the introduction of a variety of advanced technologies to the Japanese islands during the Kofun period (ca. 250â538). In the realm of pottery, highly skilled Korean makers brought both knowledge of the potterâs wheel and the technical expertise needed to create a new type of kiln now commonly known by the Japanese term anagama.
Built into a hillside with a fire fueled by wood at the lower end and a flue at the higher end, the anagama kiln fires pottery at around 1200â1400 degrees centigrade (2200â2500 F). Prior to this in Japan, pottery was fired in open or partially open trench kilns, reaching only around 800 degrees centigrade. As in Korea, the higher firing temperature resulted in stronger vessels, which replaced lower-fired wares as the standard for ceremonial and ritual purposes after the 400s. This firing environment also led to the development of natural, or âaccidental,â ash glazes, created when wood ash in the kiln collects on the vessels, creating a glaze that appears greenish-yellow to deep green, sandy to glossy, and dripping to charred. Ash glazes inspire artists around the world to this day.