Clay Selection: The clay and glaze used in Jian Zhan ceramics require a high iron content. While other kilns during the Song Dynasty attempted to replicate Jian Zhan, they often failed because the mineral composition in their local materials couldn't meet the necessary standards for producing authentic Jian Zhan.
Crushing: The prepared clay and glaze are then placed into a machine for pulverization.
Washing and Sieving: The clay or glaze should have a moderate thickness. After sieving, the clay is placed in a slurry tank, while the glaze is transferred to a glaze pool.
Chen Fu (Ceramic Terminology): Chen Fu refers to storing the clay in a room away from sunlight and air, maintaining a consistent temperature and humidity, allowing it to rest for a period.
Kneading the Clay: This step further removes air and impurities from the clay, making it denser and more uniform in moisture content. It also ensures the clay remains workable and prevents it from drying out or cracking during later stages of production.
Shaping: Shaping is typically divided into hand shaping and machine shaping.
Modification: Traditional Jian Zhan shapes usually feature a shallow circular foot. Both the base and the “inner ring” of the foot are refined using a knife.
Kiln Firing of Unglazed Jian Zhan: This step helps increase the mechanical strength of the clay while also allowing any cracked or fragile pieces to be removed in advance.
Glaze Blending: The traditional glaze formula combines natural iron ore glaze with plant ash. These simple ingredients create an exquisite glaze, yet the craft of Jian Zhan lies in using the most basic materials to form the intricate crystal patterns that make it unique.
Glazing: A distinctive feature of Jian Zhan is its half-glaze technique. Craftsmen carefully design a glaze line to control the glaze's coverage. The glazing process requires great skill—if the glaze is too thin, it won't allow crystals to form properly; if it's too thick, it could cause the glaze to stick to the bottom.
Kiln Placement: To prevent sticking, a layer of alumina powder is often placed at the bottom of the kiln.
Kiln Firing: The firing process is crucial for creating Jian Zhan. Precise control of time, temperature, and reduction frequency is essential to achieve the desired glaze color. The master must be vigilant, adjusting the reduction process and avoiding long periods of absence during firing.
Post-Kiln Finishing: After firing, defects often occur due to various factors in the production process. These imperfections must be addressed on-site. Only pieces that pass quality inspection are deemed suitable for sale.
