Longquan Ware
龙泉窑

The two production districts of Longquan celadon. The South District — centred on Dayao, Jincun, and Xikou — commands the premium tier: highest alumina content, lowest iron and titanium impurities, finest body purity. The East District (Anren, Anfu) served export and secondary production. Within the South District, Dayao wares represent the absolute summit of quality.

A millennium of kiln fire. Five Dynasties / Early Northern Song: thin, yellowish-grey glaze, primitive firing — the genesis. Late Northern Song / Southern Song: discovery of thick glaze, Powder Blue, and Plum Green — the golden age. Yuan / Early Ming: the imperial era, massive vessels, Fengdongyan official kiln. Mid-Ming / Qing: exhaustion of premium raw materials, loss of imperial favour, transition to export quality.

The body evolution. Song-period clay (low alumina, Al₂O₃ < 20%) yielded delicate, thin bodies — but collapsed at high temperatures if made too large. During the Yuan dynasty, access to more refined, weathered clay with up to 21.73% Al₂O₃ increased structural integrity, allowing the massive plates and vases that define Yuan Longquan without kiln collapse.

The chemistry of thickness. Early calcium glaze (high CaO, low K₂O) becomes highly fluid at 1300°C — it runs off the pot, preventing thick application. The Southern Song calcium-alkali glaze (lower calcium, higher potassium from plant ash) stays viscous at peak temperature, allowing artisans to dip the biscuit-fired body 3–4 times, building a glaze layer so thick it diffuses light internally — the source of the milky, jade-like opacity.

The production cycle. After shaping, the clay body undergoes taqxi (clay washing) to remove iron and titanium impurities. Biscuit firing at low temperature hardens the porous body to maximise glaze absorption. The biscuit is then dipped in glaze, dried, and dipped again — 3 to 4 times — before the final high-temperature reduction firing at 1180–1310°C in a wood-fuelled dragon kiln.

The two crowns of Longquan. Powder Blue (粉青, left): achieved through calcium-alkali viscosity — the immense glaze thickness diffuses light internally, producing a milky, jade-like opacity resembling mutton-fat nephrite. Plum Green (梅子青, right): fired at the absolute maximum temperature (1250–1280°C), the glaze fully vitrifies, trapping micro-bubbles to escape, yielding a crystalline, glassy surface of deep emerald intensity comparable to fine jadeite.

The body taxonomy. White body (left): grayish-white clay with the characteristic Vermilion Bottom (朱砂底) — a rust-red oxidation ring where the unglazed foot meets oxygen during firing. Black body (right): made with Purple Golden Clay (紫金土), 3–15% iron. The glaze physically runs thin at the rim and foot, revealing the dark iron-rich clay beneath — producing the Purple Mouth (紫口) and Iron Foot (铁足) that mark the highest Longquan imitation of imperial Guan ware.

The three primary diagnostic markers on a white-body Longquan vase. 1. Purple Mouth (紫口): glaze flows downward during firing, thinning at the rim and revealing the dark iron-rich clay beneath. 2. Ice Crackles (开片): natural fissures caused by differing shrinkage rates of glaze and clay body during cooling — not all pieces crack, but when present, the pattern should be natural and irregular. 3. Vermilion Bottom (朱砂底): the rust-red oxidation ring on the unglazed foot of white-body pieces — the iron in the local clay oxidises in the kiln's cooling phase.

The forgery tells. Authentic: natural gold-and-iron-thread crackle formed slowly by ambient cooling over centuries; soft "wet" surface luster from atmospheric exposure. Forgery: bold, unnatural black lines forced into fresh cracks using chemical ink dyes; artificially aged surfaces via acid washing leave the piece dead, overly matte, or unnaturally scratched — the antithesis of the luminous depth that defines genuine Song and Yuan Longquan.

The critical comparison: Longquan Black Body (Xikou) versus Southern Song Guan Kiln. Both share the identical Purple Mouth, Iron Foot, and crackle aesthetic — making weight and subtle glaze tone the primary physical differentiators. Guan ware is typically lighter with an extremely thin body; Longquan Xikou is heavier with denser local clay. Glaze tone: Guan leans toward grey-blue or powder blue; Longquan Xikou often displays grey-yellow or deeper green undertones.

The world's Longquan. 1. The Sinan Shipwreck: a single 14th-century sunken ship discovered off the Korean coast yielded over 9,000 Longquan pieces — the largest single archaeological haul of Chinese ceramics ever recovered. 2. Cultural reverence: a Longquan bowl broken in Japan was returned to China with iron staples — because Yongle-period artisans could no longer replicate Song quality. 3. Technology transfer: kilns in Vietnam and Thailand actively copied Longquan techniques, even forging the 'Riverbank Remnants' kiln marks.

The Ming imperial revelation. The conventional narrative — that Longquan quality collapsed after the Yuan — was overturned by excavations at the Fengdongyan official kiln site. Massive, flawlessly carved vessels were produced exclusively for the Hongwu and Yongle emperors. Shards feature strict imperial numbering systems ('Number Two', 'Three Patterns'); rejects were systematically smashed to prevent civilian use. Ming Longquan was not inferior — it was simply different in scale and intent.

The legacy triangle. Nature: the high-alumina clay and iron-rich mountain soils of the Lishui mountains — a geological gift that no other region could replicate. Alchemy: the precise engineering of calcium-alkali plant ash glazes, perfected across two centuries of Southern Song experimentation. Craft: the relentless pursuit, kiln by kiln, generation by generation, of transforming common mountain mud into something indistinguishable from eternal jade.