From Clay to Treasure: The Alchemy of Firing a Jian Zhan

Jian Zhan, as a highly distinctive craft, derives its collectible value primarily from its aesthetic appeal and firing difficulty—two aspects that are closely intertwined.

The creation of a single Jian Zhan involves 13 intricate steps, encompassing the twists and turns of the kiln master's journey, requiring not only mature firing techniques but also determination, patience, and meticulous care. 

——Raw Material Selection: 

Collect local red clay (with extremely high iron content of 7%–10%, crucial for forming the "iron body" that turns dark brown or greyish-black after firing), yellow clay (slightly lower in iron but rich in potassium and sodium, enhancing heat resistance and plasticity), and glaze ore (a natural quartz-rich mineral). These are piled outdoors for natural weathering.

——Crushing:

The weathered clay and glaze ore are crushed and finely ground to achieve an appropriate consistency.

——Washing and Purifying:

The crushed materials are washed, settled in water, and filtered to remove impurities.

——Mixing:

Washed red and yellow clay are blended in specific ratios, sometimes with other additives. The proportions determine the final body texture and quality.

——Aging: 

The mixed clay and glaze are stored indoors under controlled temperature and humidity for an extended period. This process enhances uniformity, strength, and plasticity while reducing deformation risks.

——Clay Preparation:

The aged slurry is poured into cloth bags and pressed to remove excess water, forming workable clay.

——Clay Kneading:

The clay is repeatedly kneaded into suitably sized lumps to compact it, remove air bubbles, facilitate shaping, and prevent cracking during drying.

——Forming:

Two methods are used: hand-throwing or machine molding. Hand-throwing gives each piece subtle variations, directly influencing its form. Master artisans create diverse shapes like constricted-rim or flared-rim bowls, expanding Jian Zhan’s functional range to include vases, lamp stands, and incense burners.

——Trimming:

The dried rough body is meticulously refined inside and out, often with a base inscription added. The trimmed piece is dried again, with only flawless bodies proceeding to firing.

——Bisque Firing: 

The unglazed body is fired at low temperatures (700–800°C). Cracked or deformed pieces are discarded, leaving qualified ones.

——Glazing:

Flawless bisque-fired pieces are glazed.

PS：About the glaze

Glaze Recipe: A closely guarded secret, traditionally composed of:

Jianyang Glaze Stone: Local natural quartz (mainly SiO₂), forming the glassy base.

Local Red/Yellow Clay or High-Iron Zijin Clay: The soul of coloration and crystallization. Iron elements are the origin of all patterns. Under high-temperature reduction firing, iron oxide reduces to ferrous oxide, saturating the glaze and precipitating micro-crystals whose form, size, and arrangement determine whether Hare’s Fur, Oil Spot, or other patterns emerge.

Plant Ash (e.g., pine wood/rice straw ash): The essence of traditional recipes. It lowers the melting point of glaze stone (from >1700°C to ~1300°C) and contains trace elements (phosphorus, calcium, potassium) that interact with iron to influence crystal morphology, color, and metallic luster.

Key Principles:

Thick Glaze Layer (1–3 mm, far thicker than ordinary ceramics) provides space for crystal growth.

Unglazed Foot: Only the upper exterior is glazed; the foot and surrounding area remain bare to prevent kiln adhesion (as the fluid glaze would fuse the piece to the sagger) and form "glaze tears"—a signature feature adding dynamic beauty.

Methods:

Dipping: Holding the foot, the body is briefly immersed in glaze slurry for exterior coating.

Swirling: Glaze is poured inside, swirled for even coverage, then excess is poured out.
The glazed body is dried in a cool, shaded area before sagger loading.

——Kiln Loading:

Glazed pieces are placed in saggers, separated by rice husk ash or spacers, then loaded into the kiln for firing.

——Firing:

Modern Methods: Electric or gas kilns offer better control and higher success rates.

High-End Tradition: Wood-fired dragon kilns rely heavily on the artisan’s expertise to manage temperature and atmosphere.

After dozens of hours of firing and cooling, the kiln is unloaded. The yield of finished and premium pieces remains unknown until opening.

Final Step: Finished Jian Zhan are graded by quality. Defective pieces are shattered on-site.