History of Ceramics Laboratory, Institute of Archaeology, Russian Academy ofSciences Dm. Ulianov Str. 19,. Moscow, 117036, Russia. A pottery kiln of the first ...
Modern Trends in Scientific Studies on Ancient Ceramics BAR International Series 1011, 2002
POTTERY KILN AT TELL HAZNAI AND ITS POSITION IN KILN EVOLUTION. THE CERAMICS FROM THE KILN YURI B. TSETLIN History of Ceramics Laboratory, Institute of Archaeology, Russian Academy ofSciences Dm. Ulianov Str. 19, Moscow, 117036, Russia A pottery kiln of the first half of the 3 millennium BC was discovered at Tell Hazna I in north-eastern Syria. The kiln represents a fire-construction with updraft motion of hot gases and consists of a deep fuel-firing unit, a permanent horizontal heat-conducting-and-separating unit, and a pottery-firing unit. According to Alexander A. Bobrinsky this kiln belongs to a rather early period of the pottery kiln evolution. The study of morphological and technological peculiarities of the pottery from the kiln was undertaken. Some vessels were completely handmade, while the others were also handmade but with limited (or secondary) use of a primitive potter's wheel or an acentric working support for smoothing the upper parts of the vessels. It is clear that the professional skills of local potters in making vessels by hand were well established, but the skills in using a potter's wheel were just at the first stage of mastering. rd
KEYWORDS: SYRIA, POTTERY KILN, EVOLUTION, CERAMICS, MORPHOLOGY, TECHNOLOGY, CULTURAL TRADITION
In 1990 the remains of a very well preserved pottery kiln were discovered at Tell Hazna I situated in north-eastern Syria (Fig. 1) by the Russian archaeological expedition. The main results of the study of this ancient settlement, except the ones on the kiln, have already been published (Munchaev and Merpert 1994). In the present article the results of the investigation of the kiln are considered in the following order:
Building materials usedfor the kiln Unfired bricks of two standard sizes (50x25x8 cm and 45x30x8 cm) were used for building the kiln. Microscopic analysis shows that the bricks were made from local red (iron-rich) wet clay mixed with chopped straw of cereal plants in the proportion 1 volume part of straw to 2 volume parts of wet clay. Besides, two kinds of clay mortars were used. One of the mortars was of the same composition as the bricks and the other consisted of white (iron-poor) refractory clay and straw in the above proportion. Special microscopic analysis of the ash remains showed that the straw of cereal plants cultivated by local inhabitants was most likely used as a fuel for the pottery kiln.
1) the building remains and layers, which were found during the excavation of the kiln; 2) the history of the pottery-firing structure excavated; 3) the position of the kiln in the general evolution of special structures for firing clay vessels; 4) the morphological and technological characteristics of the ceramic materials from the kiln.
BUILDING REMAINS AND OCCUPATION LAYERS, WHICH WERE FOUND IN AND AROUND THE KILN: DESCRIPTION AND INTERPRETATION
General structure of pottery kilns According to the system of pottery kiln description, which was developed by Alexander A.Bobrinsky (Bobrinsky 1991a), any pottery kiln consists of three different functional units and each of them includes both main and additional specialised devices. Here is the list of them. A pottery-firing unit consists of four specialised devices: a) pottery-firing chamber (main), b) pottery-charging device (add.), c) chimney-draft device (add.), d) firing-observation device (add.). A heat-conducting-and-separating unit consists of two specialised devices: a) separating device (main), b) heat-conducting channels (add.). A fuel-firing unit consists of five specialised devices:
Location of the kiln The pottery kiln (Fig. 2) was situated in the south-western part of the settlement (squares 19/LX-X), with remains of ash layers around it. The kiln was situated in the open yard surrounded on three sides by wall 1 on the north, by wall 5 on the south, and by later wall 3 on the east (Fig. 3). Wall 3 was built on the lower part of the ash layers. There was no wall on the west. Between walls 1 and 3 there was a passage with a semi-arched lap. In this yard two clay floors were discovered with a vertical distance of about 30 cm between them.
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Y.B. Tsetlin
a) fuel-firing chamber (main), b) fuel-charging device (main), c) heat-power concentration chamber (add.), d) heat-power distribution device (add.), e) air-draft device (add.). The following description of the excavated kiln was made according to the above system. Pottery-firing
boundary between them was level with the ancient day surface (Figs. 5 and 6). The overground part was round in shape and about 180 cm in diameter in plan. At the top the underground part was oval in shape, of a size 175x135 cm, but at the bottom it was round in shape and 110 cm in diameter. The latter part (except the bottom) was covered by plaster (3-5 cm thick) of white refractory clay, which was vitrified in some places. The overground part of the chamber contained the remains of three horizontal rows of bricks (in the upper part), two horizontal rows of bricks (in the lower part), and a compact ash layer 10-15 cm thick between them. What this means is that two separate pottery-firing structures were situated here at different times. Hereinafter the later of them is designated as "kiln A" and the earlier one as "kiln B " . Fuel-charging device: There were the remains of two such devices situated at the same place in the wall of the fuel-firing chamber, but at different levels (Figs. 5 and 6). The upper fuel-charging device was built just under the heat-conducting-and-separating unit and had the shape of a sloping channel, 60 cm high, 55 cm wide, and 50 cm deep. Its bottom was located 8 cm above the first clay floor and was covered by the compact ash layer 1012 cm thick. The lower part of this device was rectangular in shape, and its upper part was oval. Two vertical bricks limited the lower part of the device and protruded outside by 10-12 cm. Not many remains of the lower fuel-firing device were found. Perhaps it had the same construction peculiarities as the upper device, but was about 22 cm below. The bottom of the lower device was about 8 cm above the second clay floor and was covered with a compact ash layer 3-10 cm thick. The presence of these two fuel-firing devices also supports the conclusion that two pottery kilns functioned at the same place, but at different times. Important additional information was gathered by observation of the occupation layers located in the fuelfiring units of the kilns.
unit
Pottery-firing chamber: The chamber walls were built up of bricks 50x25x8 cm in size, which were laid in one row. The remaining part of its walls was 35-40 cm high. The chamber had a round and slightly conic shape with an external diameter of about 2,5 m and an internal one of 2 m. These bricks were laid horizontally and bonded by red clay mortar. In addition, the walls were completely covered by plaster of the same clay and the inner surface of the chamber was covered by a plaster of a white refractory clay up to a height of 20 cm. The way of loading and unloading the vessels is not quite clear. But the broken part of the wall of the pottery-firing chamber, its conic shape, the specific slope of the heat-conducting channels, and ethnographic data from modern pottery kilns (presented in Figure 4) show that the chamber could be of a helmet shape and could have a lateral potterycharging device displaced by 40-50 cm from the fuelcharging device to the south. Heat-conducting-and-separating
unit
The unit was about 2 m in diameter, 40 cm thick at the edges, and 30 cm thick at its centre. Originally there were 14 heat-conducting channels in it, which were located in two concentric circles, but only 10 of them have remained up to now. This unit rested on the step 10 cm wide, which stretched along its perimeter, and on the tops of two consoles about 40 cm high, which were situated on both sides of the fuel-charging device in the fuel-firing unit. The heat-conducting-and-separating unit was covered with plaster 3-5 cm thick, which consisted of two or three layers. The first (inner) layer consisted of red clay, and the second one of white refractory clay. These two layers covered all the surfaces of the unit including the channels and the lower part of the potteiy-firing chamber. The third (outer) layer of white refractory clay plaster covered only the lower and upper surfaces of the unit. The unit considered was built of whole bricks 50x25x8 cm in size and of broken ones. All the bricks were laid horizontally and joined at their large faces (Fig. 5). At first the heat-conducting channels were square in shape and only later they became round (Fig. 6). Fuel-firing
Occupation layers in the fuel-firing units (Fig. 5) There were eight different layers in this units. Layers 1, 3, and 5 consisted of red clay with small pieces of charcoal, sherds, and broken unfired bricks. All these layers were formed by usual fine dust, which filled the kilns during their non-working periods. Layers 1 and 3 belonged to the period when kiln A was out of use and layer 5 to the period when kiln B was idle. The latter layer was levelled during the building of kiln A and its surface served as a bottom of the later fuel-firing unit. Layers 2 and 6 consisted of red clay with a lot of pieces of fired broken bricks and fired or vitrified clay plaster. These layers were formed by the destruction of heat-conducting-and separating units of kiln A (layer 2) and kiln B (layer 6). Layers 4 and 7 consisted of compact grey ash only. They were formed during the direct functioning of kiln A (layer 4) and kiln B (layer 7).
unit
The fuel-firing chamber consisted of two parts: overground and underground. The overground part was made up of bricks, and the underground one was dug out in the occupation layer of the settlement. The horizontal
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Pottery kiln at Tell Hazna I and its position in kiln evolution — the ceramics from the kiln
Layer 8 contained a lot of small pieces of charcoal among ash. It was formed during the process of purposive drying and firing of the inner parts of kiln B. There was a usual occupation layer of the settlement around the fuel-firing unit of the kiln. This layer contained unfired bricks from the destroyed walls, other building debris, and a lot of pottery sherds.
Because the above two pottery kilns were found at the same place, one is inclined to think that a special pottery production area was traditionally situated there. Relative duration of using the kilns This brings up the two questions: How long was either of the kilns used and what was the interval between them? The following facts should be compared to answer the first question. Firstly, in the fuel-firing unit the upper ash layer was about twice as thick as the lower one. Secondly, in the yard the upper ash formation was three times as thick as the lower one. Thirdly, in the yard the upper ash formation contained 12 ash streaks, and the lower ash formation contained only five streaks. All these facts show that kiln A was used about two or three times longer than kiln B. If the conclusion that each of the ash streaks was formed in one firing cycle and by the subsequent cleaning of the fuel-firing chamber is right, there were only five firing cycles in kiln B and 12 cycles in kiln A. To answer the second question it is necessary to take into account that these kilns were separated by an occupation layer about 20-30 cm thick and belonged to different levels of day surfaces. This fact shows that the interval between them was quite long. But we think that this interval was no more than one generation. Some data confirms this conclusion. First, many construction components of kiln B were used for building kiln A. Second, the fuel-charging device of kiln A absolutely coincided with that of kiln B. Third, it is quite possible that the structures of both kilns were identical. Therefore it is unlikely that these two kilns were built by different potters.
Ash layers situated in the kilns yard The remains of ash layers were best preserved in the passage between walls 1 and 3, and under wall 3. Two main ash formations 30 and 10 cm thick were found one under the other in the passage. There was an occupation layer 20 cm thick between them. Either of the formations corresponded to one of the two clay floors in the yard. The upper ash formation was divided into six ash layers and each of them contained two more thin streaks. Thus, there were 12 streaks here altogether. The lower ash formation contained three layers, and out of them two lower layers consisted of two streaks each. Thus, there were five streaks in total. Each of the ash streaks was separated from the others by occupation layers of different thickness: from several millimetres to 1 cm. This is due to the fact that they were formed during different periods. A subsequent reconstruction of the history of the pottery kilns is based on the above data.
RECONSTRUCTION OF THE KILNS HISTORY (Fig. 6) History of building the kilns Kiln B was first built. A conic pit about 1 m in depth was dug into the occupation layer of the site for the fuel-firing chamber and then the inner surface was covered with a thick mortar of white clay mixed with straw. The overground part of the kiln was built of unfired bricks. There was a lateral fuel-charging device in the form of a slope channel located in the north-north-western wall of the fuel-firing unit. Probably a horizontal heatconducting-and-separating unit with special channels was in that kiln, the remains of which were found in layer 6. The other building remains of kiln B were not preserved. The lower ash formation belonged to kiln B and resulted from its operation. At one time kiln B went out of use and began to come down.
Common dating of the kilns The comparative analysis of the ceramics from the occupation layer of the site and from the kilns, which was made by Shahmardan N.Amirov, allowed one to define the functioning time of kilns A and B as First Early Dynastic Period, i.e. 2860-2600 B.C.
POSITION OF KILN A IN THE GENERAL EVOLUTION OF POTTERY-FIRING STRUCTURES (Fig. 7) In the history of pottery production there are four kinds of specialised structures for firing clay vessels: 1. Bonfire is a structure with the common working space without permanent surrounding walls. 2. Hearth is a structure with permanent walls around the common working space. 3. Stove is a structure with permanent walls around the common working place and the permanent lap over it. 4. Kiln is a structure consisting of three permanent elements: a fuel-firing unit, a heat-conducting-andseparating unit, and a pottery-firing one.
Later kiln A was built at the same place. Some remaining elements of the former fuel-firing chamber were used for it. The overground part of kiln A was also built of bricks and had the similar fuel-charging device, the horizontal heat-conducting-and-separating unit with 14 channels, and the conic pottery-firing chamber, which probably had a lateral pottery-charging device. The interior parts of kiln A were covered with two coatings: one of red low-melting clay and the other of white refractory clay. The upper ash formation was formed during the working of kiln A.
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There were three classes of pottery kilns: updraft kilns (Class I), horizontal-draft kilns (Class II), and up-andhorizontal-draft ones (Class III). The last two classes are not considered here because the above kilns belong to Class I. The different construction elements of kiln A are characterized by various degrees of their evolution. First of all the main features of evolution become apparent in fuel-firing chamber and fuel-charging device of fuelfiring unit.
Pottery-charging device: It is reconstructed hypothetically. If the reconstruction is right, this was a device of lateral type with the permanent lap. On the basis of the above data about the state of fuelfiring chamber and fuel-charging device from fuel-firing unit we can conclude that the kiln A belongs to Class I, Stage 2, Phase 3, and Level 2. In the general pottery kiln evolution (which include, according to Bobrinsky, of about one hundred steps) this state corresponds to Step 27, i.e. to a rather early period of the development of such firing structures.
Fuel-firing unit Fuel-firing chamber: Its development consisted in removing gradually the chamber from the main part of the unit. There are seven successive stages in the development of this process. The kiln A belongs to Stage 2 with the chamber of central-and-lateral type. There are three phase in the development of fuel-firing chamber inside of each stage (unformed, partly-formed, and fullyformed phases). Thus, the chamber of kiln A was fullyformed and belongs to Phase 3 of Stage 2.
CERAMIC MATERIALS FROM THE KILNS: RESULTS OF MORPHOLOGICAL AND TECHNOLOGICAL ANALYSES A lot of displaced pottery sherds were found in the kilns. They were typical of ceramics of the kiln working period. Among the sherds there are 49 samples of the upper parts of different clay vessels, which fall into two main morphological groups: group A includes the upper parts of vessels without traces of regular horizontal smoothing of the surfaces (18 vessels) (Fig. 9); group B includes the upper parts of vessels with traces of regular horizontal smoothing of the surfaces (31 vessels) (Fig. 10).
Fuel-charging device: There are 5 levels in the development of these devices. Among them the earliest ones are of upper-charging type with horizontal bottom and the latest ones are of lower-charging type with the same bottom. The devices of Levels 2 and 3 have a slope bottom. Kiln A had a fully-formed upper-fuel-charging device with a slope bottom and belongs to Level 2.
The morphological analysis Heat-power concentration chamber: This device developed by detaching gradually its construction from the fuel-firing chamber. Taking into account this parameter, we say that the heat-power concentration chamber is a partly-formed one, i.e. belongs to intermediate type.
The morphological analysis (for a detailed description of the methods see Bobrinsky 1986; 1988; 1991b) given in the present article includes the study of the vessel structure on two hierarchic levels: I. Kinds of structure are characterised by qualitative composition of the functional parts of a vessel (See Fig. 8 and Table 1).
Two other additional devices were not found during the excavation of the kiln. Heat-conducting-and-separating
unit
Separating device: It developed by replacing the temporary components of the device by permanent ones. This device of kiln A had the only permanent components, i.e. belongs to a fully-formed separating device.
Group A
Group B
L+F
22
13
L+Ch+Sh
_
L+Ch+F
34
L+Ch+N+Sh
-
16 _
47
Table 1 Mass kinds of vessel structure (> 10%)
Heat-conducting channels: These devices had the same direction of development. Kiln A is characterized by the presence of the fully-formed pipe channels. Pottery-firing
Kind of structure
II.
Variants of structure are defined by qualitative composition and degree of forming each functional part of a vessel (See Tables 2 and 3). There are three states of degree of forming a functional part: 1 - fully-formed state of the functional part, 2 partly-formed one, and 3 - unformed one. In total 12 kinds and 28 variants of the vessel structure were recorded on 49 samples of the vessel upper parts.
unit
Pottery-firing chamber: Its development consisted in increasing the usable area for placing vessels to be fired and in making special gadgets in the chamber for the same purpose. The chamber of kiln A belongs to devices of simple type.
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Pottery kiln at Tell Hazna I and its position in kiln evolution - the ceramics from the kiln
Variant of structure
Group A
Group B
L1+F1
_
7.0
L1+F2
10.0
_
L2+B1
10.0
_
L2+Ch1+N3
_
11.0
L2+Ch1+Sh1
_
7.0
L2+Ch1+F1
16.0
_
L1+N1+Sh1
10.0
_
L2+Ch1+N1+Sh1
Table 2
As we can see from Table 1, there are two mass kinds of the vessel structure (34,0% and 22,0%) in group A and three ones (47%, 16%, and 13%) in group B. Moreover, the vessels of group B have the more functional specialisation and more developed functional structure than the vessels of group A. There are eight mass variants of vessel structure, and four mass variants out of them are common for the both groups of vessels. As is seen from Table 2, this information also confirms that the vessels of group B are more specialised and more developed in structure than the vessels of group A. Now we consider the data on the degree of forming the vessel functional parts (Table 3). Although the vessels of both groups are similar by the degree of forming the functional parts, the data in Table 3 shows that the vessels of group A have a higher degree of forming their functional parts than the vessels of group B and are characterised by more stable potters' skills. Thus, the morphological analysis demonstrates that the local potters made vessels of both groups, but there was an initial specialisation among them at that time. Some potters continued to do the traditional clay vessels (group A) but the others tried to do some new unwonted forms (group B).
27.0
Mass variants of vessel structure (> 5%)
Degree of forming
Group A
Group B
the vessel functional parts 1
69.0
53.0
2
31.0
25.0
100.0
100.0
3 Total
Table 3 parts (%)
22.0
General degree offorming the vessel functional
Group A
Technological information Cream-coloured clay Natural clay
22.0
Red (iron-rich) clay
78.0
Average-sanded
83.0
High-sanded
17.0
Natural
Fine sand
44.0
inclusions
Fine limestone
22.0
100.0
Group B 42.0
100.0
94.0
10.0 100.0
29.0
in clay
Sand + Limestone
33.0
61.0
Clay + Dung
78.0
100.0
paste
Clay + Rock
6.0
Clay + Gror
17.0
-
Proportion
1 /1-2
21.0
_
of dung
1 /3-4
50.0
1 /5-6
29.0
90.0
Mechanical
Irregular smoothing
89.0
50.0
treatment
Regular horizontal smoothing
-
Firing
100.0
100.0
100.0
-
10.0
50.0
Burnishing
11.0
Oxidizing, for long-time
50.0
Oxidizing, for short-time
28.0
Reducing, for long-time
22.0
16.0
Reducing, for short-time
-
13.0
Table 4
100.0
100.0
100.0
100.0
65.0 100.0
Some technological information on ancient vessels (%)
89
100.0
6.0
Pottery
of surfaces
100.0
58.0
6.0
100.0
Y.B. Tsetlin
However, the technology of the vessels of group B was more uniform than that of the vessels of group A. But it did not refer to the traditions of selection of raw materials because those potters used equally both red (iron-rich) and cream-coloured kinds of clay. The above facts have led us to the conclusion that the skills of making the vessels of group B were brought to the settlement by other potters. On the one hand, they were like the local potters by their pottery cultural traditions and on the other hand they had a rather high level of pottery technology. It is possible that they were inhabitants of one of the neighbouring urban settlements. Thus, the studies of pottery kilns and the ceramic materials from them have helped to elucidate the history of ancient cultural traditions in pottery production and the history of their keepers.
The technological analysis The technological analysis presented in this article describes the following steps of the pottery making process. Selection of raw materials: The relative amount of iron and sand in clay and the composition of coarse natural tempers (>0,1 mm) are studied here. Making pottery paste: The analysis includes the study of added tempers and their proportion in clay. Treatment of vessel surface: Some mechanical methods of surface treatment are studied here. Imparting watertightness and strength to clay vessels: We study here some peculiarities of the atmosphere and the duration of the firing process. At first the specific technological traces in (or on) ancient sherds were analysed by a binocular microscope of 5 - 56 power. Then the discovered traces were compared with the traces in (or on) experimental patterns in the History of Ceramics Laboratory (Moscow, Russia). The results of the technological study are given in Table 4. As the data in Table 4 shows, there is some difference between the vessels of groups A and B.
ACKNOWLEDGEMENTS I am very grateful to RM.Munchaev (the head of the Russian Archaeological Expedition in Syria) for permission to make use of the unpublished data in my paper and to A.A.Bobrinsky (the head of the History of Ceramics Laboratory at the Institute of Archaeology of the Russian Academy of Sciences) for his useful comments.
Vessels of group A To make these vessels ancient potters used mainly the red (iron-rich) low-melting and averaged-sanded clay mixed with goats and sheep dung in the proportion of 1 part of dung to 3-4 parts of wet clay. Random smoothing of the upper parts of the vessels was made. The potters used an oxidising firing of the vessels during various holding time under red heat conditions.
REFERENCES Bobrinsky A.A. 1986, On the method of study of vessel's shape from archaeological excavations. Cultures of Eastern Europe of the 1 millennium AD, Kuibyshev, 137-157 (in Russian). Bobrinsky A.A., 1988, The functional parts of vessel's shape. The problems of study of archaeological ceramics, Kuibyshev, 5-21 (in Russian). Bobrinsky A.A., 1991a, Pottery workshops and kilns in Eastern Europe (by the material of the 2 -5 centuries AD), Moscow (in Russian). Bobrinsky A.A., 1991b, The envelopes of clay vessels' functional parts, Archaeological studies in foreststeppe zone of Volga basin, 3-35, Samara (in Russian). Munchaev R.M., Merpert N.Ya. 1994, Da Hassuna a Accad. Scavi della missione russa nella regione di Hassake, Siria di NE 1988-1992. Mesopotamia, XXTX, Firenze, 5-48. st
Vessels of group B For these vessels ancient potters used average-sanded red (iron-rich) and cream-coloured kinds of clays. The latter had natural inclusions of fine sand and fine limestone. As added temper they used goats and sheep dung in a proportion of 1 part of dung to 5-6 parts of wet clay, mainly. Both random and regular horizontal smoothing of the upper parts of the vessels were made. The potters used either oxidising firing only or oxidising firing with a reducing (or incompletely reducing) atmosphere at the end of the firing process.
nd
GENERAL RESULTS OF THE CERAMICS STUDY Although the vessels of groups A and B are quite similar, they have the differences in some morphological and technological features. Thus, the morphology of the vessels of group A is characterised by a more homogeneous composition and by a higher degree of forming the functional parts than the vessels of group B. The potters, who made the vessels of group B, could use an acentric working support or a primitive potter's wheel for smoothing the upper parts of vessels.
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th
Pottery kiln at Tell Hazna I and its position in kiln evolution - the ceramics from the
TURKEY
Figure 1
Location of Tell Hazna I in north-eastern Syria
Figure 2 General view of the excavated pottery kiln at Tell Hazna I (1990)
Figure 3 Location of the studied pottery kiln (N° 15) at Tell Hazna I
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Y.B. Tsetlin
Pottery kiln at Tell Hazna I and its position in kiln evolution - the ceramics from the kiln
Stage 7
Stage 6
Stage 5
Stage 3-4
Stage 2
Stage lb
Stage la Kilns of Class 1
Stove Hearth
Figure 9 Some vessels of group A
Bonfire
Figure 7 Place of the excavated kilns in general evolution ofpottery firing structures
Up(L) Cheek (Ch)
Shoulder (Sh)
fcmmct(f)
Figure 8 Functional parts of a vessel. Full structure of a vessel includes seven functional parts: L+Ch+N+Sh+F+B+Bb
Bo4y{B)
Body Base (Bb)
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Y.B. Tsetlin
Figure 10 Some vessels of group B
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