IṢẸ́ ỌNÀ
ẸWÀ ÀTI ÌLERA
IṢẸ́ ỌWỌ́
ÀṢÀ ÀTI ÌTÀN
ÌṢERÉ
ÀYÍKÁ
OÚNJẸ ÀTI OHUN MÍMU
REVERSE ENGINEERING
SÁYẸ́ǸSÌ
ERÉ ÌDÁRAYÁ
ÌMỌ̀-Ẹ̀RỌ
ÀWỌN OHUN WÍWỌ̀
Longquan Celadon Bowls: Glaze of Glaze Stone, Husk-and-Lime Ash and Zijin Clay, Reduction Fired
Longquan celadon, made in Longquan, China, since the 10th century, is a thick jade-green glaze over a bisque-fired body. The glaze is three powders washed out of local materials: glaze stone, the ash of rice husk burnt together with limestone, and iron-rich Zijin clay. Fired in reduction between 900 and 1230 °C, the iron in the glaze turns blue-green.
Result: thick-glazed, jade-green celadon bowls.
Source: the video 'Longquan celadon' by Shanbai (2025), checked frame by frame against its captions. Not given: amounts, the glaze proportion, ageing times, how iron is taken out, firing times. Unknown: the clay body of the bowls; the video does not show it. Photo: Southern Song Longquan bowl, Royal Ontario Museum, by Daderot (CC0).
Ilọsíwájú
several weeks
Ìlànà
1
1
Watch: Longquan celadon from stone to bowl
Watch: Longquan celadon from stone to bowl
The whole process in eight minutes, by Shanbai: preparing the three glaze materials, throwing and bisque firing the bowls, glazing, and the reduction firing.
2
2
Pound the glaze stone
Pound the glaze stone
Crush the glaze stone in a stone mortar with a foot-trodden pestle.
Àwọn ohun èlò fún ìgbésẹ̀ yìí:
Òkúta fún glaze1 as requiredÀwọn irinṣẹ́ tí a nílò:
Odó tí a ń tẹ̀ lẹ́sẹ̀3
3
Sieve and settle the stone
Sieve and settle the stone
Sieve the crushed stone and pound the coarse bits again. Stir the fine stone into water in a vat, sieve off the fine particles suspended in the water into another vat, and let them settle.
Àwọn irinṣẹ́ tí a nílò:
Àkójọ ajọ̀ (ihò onípele)
Omi
Ìkòkò Seramiiki Onídìí
Ṣíbí ńlá4
4
Burn rice husk with limestone
Burn rice husk with limestone
In a brick-edged bed outdoors, lay rice husk and limestone in alternate layers and burn them. Turn the materials several times during the firing so the husk burns completely.
Àwọn ohun èlò fún ìgbésẹ̀ yìí:
Èèpo ìrẹsì1 as required
Bílọ́ọ̀kì òkúta ẹfun1 as requiredÀwọn irinṣẹ́ tí a nílò:
Bíríkì
Ọkọ́5
5
Sieve and wash the ash
Sieve and wash the ash
Sieve the ash into a vat. Add water and ladle it through a fine sieve into a fresh vat. While this 'black glaze' settles, change the water and wash it several times.
Àwọn irinṣẹ́ tí a nílò:
Àkójọ ajọ̀ (ihò onípele)Ìkòkò Seramiiki OnídìíOmiṢíbí ńlá6
6
Mill and settle the Zijin clay
Mill and settle the Zijin clay
Grind the dry Zijin clay to powder in a stone hand mill. Mix it well with water, sieve it into a fresh vat and let the fine particles settle.
Àwọn ohun èlò fún ìgbésẹ̀ yìí:
Amọ̀ Zijin1 as requiredÀwọn irinṣẹ́ tí a nílò:
Ọlọ Òkúta Ọwọ́OmiÀkójọ ajọ̀ (ihò onípele)Ìkòkò Seramiiki Onídìí7
7
Dewater in bags, then age
Dewater in bags, then age
Drain the water off each of the three vats without stirring up the settled powder. Scoop each paste into a cloth bag, lay the bags on a board and press them under a millstone. When they are dewatered to a certain degree, let them age for a while. Not given: how long. Ours: linen bags (as in the transcript).
Àwọn irinṣẹ́ tí a nílò:
Ṣíbí ńlá
Àpò ọ̀gbọ̀
Òkúta ọlọ ọwọ́8
8
Throw the bowls
Throw the bowls
Throw the bowls on the wheel and let them air-dry in the shade. Unknown: the clay body; the video does not show what it is or how it is made.
Àwọn ohun èlò fún ìgbésẹ̀ yìí:
Ara amọ̀ àìmọ̀1 as requiredÀwọn irinṣẹ́ tí a nílò:
Kẹ̀kẹ́ oníṣẹ́ ìkòkò9
9
Trim and stamp
Trim and stamp
Set each dry bowl upside down on a chuck on the wheel, trim the outside and the foot smooth, and stamp your mark in the foot.
Àwọn irinṣẹ́ tí a nílò:
Kẹ̀kẹ́ oníṣẹ́ ìkòkò
Ohun èlò ìyípo igi tútù
Èdìdì amọ̀kòkò10
10
Bisque fire at about 800 °C
Bisque fire at about 800 °C
Stack the bowls in the kiln, brick up the door and seal it with mud, and fire with wood to about 800 °C. The bisque firing makes the body stronger and more absorbent, so the glaze takes better.
Àwọn irinṣẹ́ tí a nílò:
Ìléru ÌsunBíríkì
Igi Ìdáná
Pirómítà11
11
Make the glaze
Make the glaze
Mix the burnt husk-and-lime ash, the glaze stone and the Zijin clay in proportion, add about an equal amount of water, stir and grind fine. Sieve it, take out the iron, and let the glaze age in the glaze vat. Not given: the proportion, how the iron is removed, how long it ages. Rice husk ash, glaze stone and Zijin clay give the silica, feldspar and kaolin; Zijin clay's iron is the colourant; lime and the potash and soda of feldspar lower the melting point.
Àwọn irinṣẹ́ tí a nílò:
Odó àti Ọmọ Odó ÒkútaOmiÀkójọ ajọ̀ (ihò onípele)Ìkòkò Seramiiki Onídìí12
12
Dip the bowls
Dip the bowls
Hold each bisque bowl with wire tongs and dip it into the glaze. Let it air-dry.
Àwọn irinṣẹ́ tí a nílò:
Ẹ̀mú ìrìbọmiÌkòkò Seramiiki Onídìí13
13
Spray on more glaze
Spray on more glaze
Set the bowl upside down on a chuck on the wheel and spray glaze evenly over the outside with a mouth-blown sprayer. Repeated bisque firings, dipping and thin spray coats build a thick glaze; Longquan celadon is a lime-alkali glaze that stays put at high temperature. Scrape the glaze off the foot with a knife.
Àwọn irinṣẹ́ tí a nílò:
Kẹ̀kẹ́ oníṣẹ́ ìkòkò
Ohun ìfọ́n dídán tí a fẹ́nu fẹ́
Ọ̀bẹ14
14
Reduction fire in saggars
Reduction fire in saggars
Set the bowls in saggars, stack them in the kiln and seal the door. Between 900 °C and 1230 °C, feed fuel often, and when combustion is insufficient fire in reduction: the iron in the glaze gives up oxygen, and the mix of divalent and trivalent iron turns the glaze blue-green. Not given: how long the firing takes.
Àwọn irinṣẹ́ tí a nílò:
Àpótí amọ̀-ináÌléru ÌsunBíríkìIgi ÌdánáPirómítàÀwọn ohun-èlò
5- 1 as requiredÀyè
- 1 as requiredÀyè
- 1 as requiredÀyè
- 1 as requiredÀyè
- 1 as requiredÀyè
Àwọn irinṣẹ́ tó nílò
21- Àyè
- Àyè
- Àyè
- Àyè
- Àyè
- Àyè
- Àyè
- Àyè
- Àyè
- Àyè
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