Ubufatanye
UBUHANZI
UBWIZA N'UBUZIMA
UBUKORIKORI
UMUCO N'AMATEKA
IMYIDAGADURO
IBIDUKIKIJE
IBIRIBWA N'IBINYOBWA
UBWUBATSI BUSUBIRA INYUMA
UBUMENYI
SIPORO
IKORANABUHANGA
IBYAMBARWA
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).
Hejuru
several weeks
Amabwiriza
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.
Ibikoresho by'iyi ntambwe:
Ibuye ry'irangi ryaka1 as requiredIbikoresho bikenewe:
Isekuru ikandagirwa3
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.
Ibikoresho bikenewe:
Agatsiko k'utuyungurizo (imyobo itandukanye)
Amazi
Icyombo cya seramike gifite umufuniko
Ikiyiko kinini4
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.
Ibikoresho by'iyi ntambwe:
Ibishishwa by'umuceri1 as required
Igice cy'ibuye ry'ishwagara1 as requiredIbikoresho bikenewe:
Itafari
Isuka5
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.
Ibikoresho bikenewe:
Agatsiko k'utuyungurizo (imyobo itandukanye)Icyombo cya seramike gifite umufunikoAmaziIkiyiko kinini6
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.
Ibikoresho by'iyi ntambwe:
Ibumba rya Zijin1 as requiredIbikoresho bikenewe:
Urusyo rw'Ibuye rw'IntokiAmaziAgatsiko k'utuyungurizo (imyobo itandukanye)Icyombo cya seramike gifite umufuniko7
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).
Ibikoresho bikenewe:
Ikiyiko kinini
Agafuka ka lino
Ibuye ryo gusya ry'intoki8
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.
Ibikoresho by'iyi ntambwe:
Ibumba ry'umubiri ritazwi1 as requiredIbikoresho bikenewe:
Uruziga rw'umubumbyi9
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.
Ibikoresho bikenewe:
Uruziga rw'umubumbyi
Ibikoresho byo kubaza ibiti bibisi
Kashe y'umubumbyi10
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.
Ibikoresho bikenewe:
ItanuraItafari
Inkwi
Pirometero11
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.
Ibikoresho bikenewe:
Isekuru n'Umuhini by'IbuyeAmaziAgatsiko k'utuyungurizo (imyobo itandukanye)Icyombo cya seramike gifite umufuniko12
12
Dip the bowls
Dip the bowls
Hold each bisque bowl with wire tongs and dip it into the glaze. Let it air-dry.
Ibikoresho bikenewe:
Ingofero yo kwinikaIcyombo cya seramike gifite umufuniko13
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.
Ibikoresho bikenewe:
Uruziga rw'umubumbyi
Igitera irangi gihuhwa n'umunwa
Icyuma14
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.
Ibikoresho bikenewe:
Agasanduku k'ibumba ryihanganira umuriroItanuraItafariInkwiPirometeroIbikoresho
5- 1 as requiredUmwanya
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Ibikoresho bikenewe
21- Umwanya
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- Umwanya
- Umwanya
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- Umwanya
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Iki gishushanyo gikora
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