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44-468: Tenmoku (天目, also spelled "temmoku" and "temoku") is a type of glaze that originates in imitating Chinese Jian ware (建盏) of the southern Song dynasty (1127–1279), original examples of which are also called tenmoku in Japan. Jian ware tea bowl shapes are conical in form with a slight indent below the rim. They are about 4–5 inches (10–13 cm) in height. The emphasis is on the ceramic glaze , where

88-428: A tunnel kiln , is long with only the central portion directly heated. From the cool entrance, ware is slowly moved through the kiln, and its temperature is increased steadily as it approaches the central, hottest part of the kiln. As it continues through the kiln, the temperature is reduced until the ware exits the kiln nearly at room temperature. A continuous kiln is energy-efficient, because heat given off during cooling

132-593: A Song Jian ware tea-bowl of the yuteki tenmoku type, long in the Japanese Kuroda family collection, was auctioned at Christie's New York for over $ US11 million. The pre-sale estimate was $ US1.5 to 2.5 million. The bowl was registered by the Japanese government as an Important Art Object on 18 December 1935 and deregistered on 4 September 2015 for the sale. The wares were made using local iron-rich clays and fired in an oxidising atmosphere at temperatures in

176-460: A key factor in the development of Chinese pottery , and until recent centuries was the most advanced in the world. The Chinese developed kilns capable of firing at around 1,000 °C before 2000 BCE . These were updraft kilns, often built below ground. Two main types of kiln were developed by about 200 AD and remained in use until modern times. These are the dragon kiln of hilly southern China , usually fuelled by wood, long and thin and running up

220-645: A number of distinct effects can be produced, some including an element of randomness that has a philosophical appeal to the Japanese. The tea-masters who developed the Japanese tea ceremony promoted the aesthetic underlying tenmoku pottery. Tenmoku takes its name from the Tianmu Mountain (天目 Mandarin : tiān mù ; Japanese: ten moku ; English: Heaven's Eye) temple in China where iron-glazed bowls were used for tea. The style became widely popular during

264-530: A range of firing conditions. Both Ancient Roman pottery and medieval Chinese pottery could be fired in industrial quantities, with tens of thousands of pieces in a single firing. Early examples of simpler kilns found in Britain include those that made roof-tiles during the Roman occupation. These kilns were built up the side of a slope, such that a fire could be lit at the bottom and the heat would rise up into

308-669: A single-firing in a large dragon kiln . One such kiln, built on the side of a steep hill, was almost 150 metres in length, although most Jian dragon kilns were shorter than 100 metres. The style of Jian ware has been much imitated over the last century, in Japan, the West, and recently also in China. Starting in the 1990s, the Ji Yu Fang Lao Long factory outside of Wuyishan, Fujian in the village of Shui Ji under Master Xiong has been able to restart production of Jian Zhan using

352-418: A slope, and the horseshoe-shaped mantou kiln of the north Chinese plains, smaller and more compact. Both could reliably produce the temperatures of up to 1300 °C or more needed for porcelain . In the late Ming, the egg-shaped kiln or zhenyao was developed at Jingdezhen and mainly used there. This was something of a compromise between the other types, and offered locations in the firing chamber with

396-448: Is a thermally insulated chamber, a type of oven , that produces temperatures sufficient to complete some process, such as hardening, drying, or chemical changes . Kilns have been used for millennia to turn objects made from clay into pottery , tiles and bricks . Various industries use rotary kilns for pyroprocessing (to calcinate ores, such as limestone to lime for cement ) and to transform many other materials. According to

440-490: Is called Jian zhan ( 建盏 ), which translates as "Jian (tea)cup". The original kiln was called Jian Yao ( 建窑 ). The original prefecture where it came from was then renamed into Jianzhou ( 建州 ) in 621 CE during the Tang dynasty . The ware therefore became also known based on its origin as Jianzhou zhan ( 建州盏 ). The Song dynasty scholar and Fujian native Cai Xiang (1012–1067) noted in his " The Record of Tea ": Tea

484-420: Is made of feldspar , limestone , and iron oxide . The more quickly a piece is cooled, the blacker the glaze will be. Tenmoku s are known for their variability. During their heating and cooling, several factors influence the formation of iron crystals within the glaze. A long firing process and a clay body which is also heavily colored with iron increase the opportunity for iron from the clay to be drawn into

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528-428: Is of light colour and looks best in black cups. The cups made at Jianyang are bluish-black in colour, marked like the fur of a hare . Being of rather thick fabric they retain the heat, so that when once warmed through they cool very slowly, and they are additionally valued on this account. None of the cups produced at other places can rival these. Blue and white cups are not used by those who give tea-tasting parties. At

572-444: Is often provided early in the schedule to supplement the dehumidifier. Solar kilns are conventional kilns, typically built by hobbyists to keep initial investment costs low. Heat is provided via solar radiation, while internal air circulation is typically passive. Vacuum and radio frequency kilns reduce the air pressure to attempt to speed up the drying process. A variety of these vacuum technologies exist, varying primarily in

616-404: Is recycled to pre-heat the incoming ware. In some designs, the ware is left in one place, while the heating zone moves across it. Kilns in this type include: In the intermittent kiln , the ware is placed inside the kiln, the kiln is closed, and the internal temperature is increased according to a schedule. After the firing is completed, both the kiln and the ware are cooled. The ware is removed,

660-416: Is removed by a system of vents, the specific layout of which are usually particular to a given manufacturer. In general, cool dry air is introduced at one end of the kiln while warm moist air is expelled at the other. Hardwood conventional kilns also require the introduction of humidity via either steam spray or cold water misting systems to keep the relative humidity inside the kiln from dropping too low during

704-676: Is slowly brought to a maximum temperature by adding fuel, then fueling is stopped and the kiln is allowed to cool slowly by losing heat to the air around it. To fire down a kiln, the potter continues to add a limited amount of fuel after the maximum temperature is reached to slow the cooling process and keep the glazes molten for as long as possible. Tenmoku glazes can range in color from dark plum (persimmon), to yellow, to brown, to black. The most common types of glaze are: "Chinese Glazes", Nigel Wood, A& C Black, 1999. Jian temmoku, pages 145–158. [REDACTED] Media related to Tenmoku at Wikimedia Commons Jian ware In Chinese it

748-509: Is still produced in Japan amongst a very small circle of artists, one being Kamada Kōji (鎌田幸二). Others are Nagae Sōkichi (長江惣吉), Hayashi Kyōsuke (林恭助), and Oketani Yasushi (桶谷寧). In the 1990s, renewed interest in the Jian ware in China means that masters such as Xiong Zhonggui in the village of Shuiji in Fujian has been able to restart production of Jian Zhan using the original raw materials. It

792-841: The Oxford English Dictionary , kiln was derived from the words cyline, cylene, cyln(e) in Old English , in turn derived from Latin culina ("kitchen"). In Middle English , the word is attested as kulne, kyllne, kilne, kiln, kylle, kyll, kil, kill, keele, kiele. In Greek the word καίειν, kaiein , means 'to burn'. The word "kiln" was originally pronounced "kil" with the "n" silent, as is referenced in Webster's Dictionary of 1828 and in English Words as Spoken and Written for Upper Grades by James A. Bowen 1900: "The digraph ln, n silent, occurs in kiln. A fall down

836-759: The Song dynasty . In Chinese it is called Jian Zhan (建盏), which means "Jian (tea)cup". According to chronicles in 1406, the Yongle Emperor (1360–1424) of the Ming dynasty sent ten Jian ware bowls to the shōgun Ashikaga Yoshimitsu (1358–1408), who ruled during the Muromachi period . A number of Japanese monks who traveled to monasteries in China also brought pieces back home. As they became valued for tea ceremonies, more pieces were imported from China where they became highly prized goods. Three of these vessels from

880-405: The glaze . While the glaze is molten, iron can migrate within the glaze to form surface crystals, as in the "oil spot" glaze, or remain in solution deeper within the glaze for a rich glossy color. Oil spots are more common in an oxidation firing. A longer cooling time allows for maximum surface crystals. Potters can "fire down" a kiln to help achieve this effect. During a normal firing, the kiln

924-421: The southern Song dynasty are so highly valued that they were included by the government in the list of National Treasures of Japan (crafts: others) . The style was eventually produced in Japan as well, where it endures until this day. The Japanese term gradually replaced the original Chinese one for general ware of the type. Of particular renown were the kilns that produced tenmoku are Seto ware . The glaze

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968-548: The air in the chamber is then heated and finally a vacuum is pulled as the charge cools. SSV run at partial-atmospheres, typically around 1/3 of full atmospheric pressure, in a hybrid of vacuum and conventional kiln technology (SSV kilns are significantly more popular in Europe where the locally harvested wood is easier to dry than the North American woods.) RF/V (radio frequency + vacuum) kilns use microwave radiation to heat

1012-465: The clay until the particles partially melt and flow together, creating a strong, single mass, composed of a glassy phase interspersed with pores and crystalline material. Through firing, the pores are reduced in size, causing the material to shrink slightly. In the broadest terms, there are two types of kilns: intermittent and continuous, both being an insulated box with a controlled inner temperature and atmosphere. A continuous kiln , sometimes called

1056-437: The differential impact of the presence of drying equipment in a specific plant. Every piece of equipment from the green trimmer to the infeed system at the planer mill is part of the "drying system". The true costs of the drying system can only be determined when comparing the total plant costs and risks with and without drying. Kiln dried firewood was pioneered during the 1980s, and was later adopted extensively in Europe due to

1100-581: The drying cycle. Fan directions are typically reversed periodically to ensure even drying of larger kiln charges. Most softwood kilns operate below 115 °C (239 °F) temperature. Hardwood kiln drying schedules typically keep the dry bulb temperature below 80 °C (176 °F). Difficult-to-dry species might not exceed 60 °C (140 °F). Dehumidification kilns are similar to other kilns in basic construction and drying times are usually comparable. Heat comes primarily from an integral dehumidification unit that also removes humidity. Auxiliary heat

1144-429: The economic and practical benefits of selling wood with a lower moisture content (with optimal moisture levels of under 20% being much easier to achieve). The total (harmful) air emissions produced by wood kilns, including their heat source, can be significant. Typically, the higher the temperature at which the kiln operates, the larger the quantity of emissions that are produced (per mass unit of water removed). This

1188-539: The history and cultural heritage in China has revived starting in the 1990s. At the Jiyufang Laolong site ( 吉玉坊老龍窯 ), located in a village near the town of Shuiji not far from Wuyishan , Master Xiong Zhonggui has been able to restart production of Jian Zhan using original clay, after studying with Japanese maskers. Kilns in Dehua County are also attempting in recreating it. On 15 September 2016

1232-464: The kiln can kill you." Bowen was noting that "kill" and "kiln" are homophones . Pit fired pottery was produced for thousands of years before the earliest known kiln, which dates to around 6000 BCE , and was found at the Yarim Tepe site in modern Iraq . Neolithic kilns were able to produce temperatures greater than 900 °C (1652 °F). Uses include: Kilns are an essential part of

1276-431: The kiln charge, and typically have the highest operating cost due to the heat of vaporization being provided by electricity rather than local fossil fuel or waste wood sources. The economics of different wood drying technologies are based on the total energy, capital, insurance/risk, environmental impacts, labor, maintenance, and product degradation costs. These costs, which can be a significant part of plant costs, involve

1320-464: The kiln is cleaned and the next cycle begins. Kilns in this type include: Kiln technology is very old. Kilns developed from a simple earthen trench filled with pots and fuel pit firing , to modern methods. One improvement was to build a firing chamber around pots with baffles and a stoking hole. This conserved heat. A chimney stack improved the air flow or draw of the kiln, thus burning the fuel more completely. Chinese kiln technology has always been

1364-411: The kiln. Traditional kilns include: With the industrial age , kilns were designed to use electricity and more refined fuels, including natural gas and propane . Many large industrial pottery kilns use natural gas, as it is generally clean, efficient and easy to control. Modern kilns can be fitted with computerized controls allowing for fine adjustments during the firing. A user may choose to control

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1408-517: The kiln. Most softwood kilns are track types in which the timber is loaded on kiln/track cars for loading the kiln. Modern high-temperature, high-air-velocity conventional kilns can typically dry 1-inch-thick (25 mm) green wood in 10 hours down to a moisture content of 18%. However, 1-inch-thick green red oak requires about 28 days to dry down to a moisture content of 8%. Heat is typically introduced via steam running through fin/tube heat exchangers controlled by on/off pneumatic valves. Humidity

1452-435: The manufacture of almost all types of ceramics . Ceramics require high temperatures so chemical and physical reactions will occur to permanently alter the unfired body. In the case of pottery, clay materials are shaped, dried and then fired in a kiln. The final characteristics are determined by the composition and preparation of the clay body and the temperature at which it is fired. After a first firing, glazes may be used and

1496-399: The method heat is introduced into the wood charge. Hot water platten vacuum kilns use aluminum heating plates with the water circulating within as the heat source, and typically operate at significantly reduced absolute pressure. Discontinuous and SSV (super-heated steam) use atmosphere pressure to introduce heat into the kiln charge. The entire kiln charge comes up to full atmospheric pressure,

1540-434: The moisture content is between 18% and 8%. This can be a long process unless accelerated by use of a kiln. A variety of kiln technologies exist today: conventional, dehumidification, solar, vacuum and radio frequency. Conventional wood dry kilns are either package-type (side-loader) or track-type (tram) construction. Most hardwood lumber kilns are side-loader kilns in which fork trucks are used to load lumber packages into

1584-573: The original raw materials. People in Dehua County are also attempting in recreating it. Notably, the Taiwanese American ceramics master Chun Wen Wang has successfully recreated the Jian ware and tenmoku styles through a mix of modern technology and ancient research. His work has been recognized to be a faithful recreation of the Jian ware style and collected by multiple eminent international museums. [REDACTED] Media related to Jian ware at Wikimedia Commons Kiln A kiln

1628-553: The pattern called "hare's fur". When Jian wares were set tilted for firing, drips run down the side, creating pooling of the liquid glaze, which is retained after firing. A "hare's fur" Jian tea bowl in the Metropolitan Museum of Art was made during the Song dynasty (960–1279) and exhibits the typical pooling, or thickening, of the glaze near the bottom. The "hare's fur" patterning in the glaze of this bowl resulted from

1672-510: The random effect of phase separation during early cooling in the kiln and is unique to this bowl. This phase separation in the iron-rich glazes of Chinese blackwares was also used to produce the well-known "oil-spot" ( 油滴 ), "teadust" and "partridge-feather" ( 鷓鴣斑 ) glaze effects. No two bowls have identical patterning. The bowl also has a dark brown "iron-foot" which is typical of this style. It would have been fired, probably with several thousand other pieces, each in its own stackable saggar , in

1716-478: The rate of temperature climb or ramp , hold or soak the temperature at any given point, or control the rate of cooling. Both electric and gas kilns are common for smaller scale production in industry and craft, handmade and sculptural work. Modern kilns include: Green wood coming straight from the felled tree has far too high a moisture content to be commercially useful and will rot, warp and split. Both hardwoods and softwood must be left to dry out until

1760-432: The region of 1,300 °C (2,370 °F). The glaze was made using clay similar to that used for forming the body, except fluxed with wood- ash . They share some similarities with Jizhou ware , which developed around the same time. Many examples have distinct finishes in the glaze, which are much prized by collectors. The main three types of glaze patterns are: At high temperatures the molten glaze separates to produce

1804-569: The time, tea was prepared by whisking powdered leaves that had been pressed into dried cakes together with hot water, which was somewhat akin to matcha in the Japanese tea ceremony . The water added to this powder produced a white froth that would stand out better against a dark bowl. Jian ware reached the peak of its popularity during the Song dynasty. Vessels of this time were also greatly appreciated and copied in Japan, where they are known as tenmoku ( 天目 ) wares. The Japanese term derives from Tianmu Mountain ( 天目山 ), where this type of vessel

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1848-466: The ware is fired a second time to fuse the glaze into the body. A third firing at a lower temperature may be required to fix overglaze decoration. Modern kilns often have sophisticated electronic control systems, although pyrometric devices are often also used. Clay consists of fine-grained particles that are relatively weak and porous. Clay is combined with other minerals to create a workable clay body. The firing process includes sintering . This heats

1892-400: Was prepared by steeping whole leaves in boiling water - a process that led to the invention of the teapot and subsequent popularity of Yixing wares over the dark tea bowls. While in China the art of Jian ware faded and then died out, in Japan it continued and became the foremost producer of this type of ware, also due to the importance and development of the tea ceremony. Renewed interest in

1936-604: Was supposed to originate from and be appreciated. Five of these vessels that originate during the southern Song dynasty are so highly valued that they were included by the government in the list of National Treasures of Japan (crafts: others) . Tastes in preparation changed during the Ming dynasty; the Hongwu Emperor (1328–1398) himself preferred leaves to powdered cakes, and would accept only leaf tea as tribute from tea-producing regions. Leaf tea, in contrast to powdered tea,

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