The Journal of Korean Art and Archaeology

Introduction

The Gilt-bronze Standing Avalokitesvara Bodhisattva (Figs. 1-1 through 1-3), National Treasure No. 293, was excavated along with another gilt-bronze sculpture of a standing bodhisattva in 1907 from Gyuam-ri, Gyuam-myeon, Buyeo-gun, Chungcheongnam-do Province. This sculpture presumably was put up for sale by the Japanese military police, passed through many hands, and came to be owned by a Japanese man named Niwase Hiroaki (庭瀬博章) or Niwase Nobuyuki (庭瀬信行), who was active in Joseon during the period of Japanese colonial rule. After Korea’s liberation, the sculpture entered the collection of the National Museum. Currently, it is displayed at the permanent exhibition hall in the Buyeo National Museum.

The sculpture is 21.1 centimeters high, 7.5 centimeters wide, and weighs 860 grams. Since there is a representation of a transformed Buddha within the crown on his head, the main statue standing atop of a round lotus pedestal appears to have been produced as Avalokitesvara Bodhisattva. The inside of the pedestal is hollowed out, while the parts where the pedestal and the statue are connected are plugged. This indicates the statue section is filled with cast metal. The thickness of the pedestal measures 2.8 millimeters at the thinnest and 7.3 millimeters at the thickest, but overall, it is very thin. There is even a hole in one of the thinner sections.

The other gilt-bronze sculpture of Avalokitesvara Bodhisattva (Fig. 2), excavated along with the first one mentioned above, is known to have been purchased and owned by a Japanese man named Ichida Jirō (市田次郞), who lived in Daegu during the Japanese colonial era. Before Korea’s liberation, Ichida brought it with him to Japan. Afterwards, its whereabouts were unknown. However, the media revealed recently that the sculpture is in the possession of another Japanese person, which drew considerable attention.

A comparison between these two gilt-bronze bodhisattva sculptures shows that the sculpture in Japan features a more natural facial expression, drapery, and posture than the one in possession of the Buyeo National Museum. Moreover, they differ in the connecting method of the figure to the pedestal. The main statue and pedestal of the Buyeo sculpture were cast at one time as a single unit, whereas in the case of the other sculpture, the pedestal was cast separately and attached to the figure later. Thus, despite the same excavation location, taking into account the clear differences in the natural depiction and the casting method used to connect the figure to the pedestal, these two gilt-bronze bodhisattva sculptures appear to have been produced at different times. In other words, these two sculptures are not contemporaneous. Considering the realistic body depiction, naturally flowing drapery folds, and sophisticated ornaments of the sculpture in Japan, the sculpture at at the Buyeo National Museum was likely produced earlier than the former. Further scientific research on the sculpture in Japan would enrich a comparative study with the Buyeo sculpture.

Fig. 1-1. Gilt-bronze Standing Bodhisattva (front)

Fig. 1-2. Gilt-bronze Standing Bodhisattva (back)

Fig. 1-3. Gilt-bronze Standing Bodhisattva (detail)

Fig. 2. Gilt-bronze Standing Bodhisattva in Japan

This paper intends to explore the structure, casting method, material components, and surface treatment method of the Giltbronze Standing Avalokitesvara Bodhisattva excavated from Gyuam-ri, Buyeo, and currently housed at the Buyeo National Museum (hereafter, Gilt-bronze Standing Bodhisattva) by examining it under a microscope and through nondestructive analysis and X-ray radiation.

Survey Methods

The form of the Gilt-bronze Standing Bodhisattva was examined at a magnification of 7.8 through an optical microscope (Leica M205A, Germany). The components of the statue’s base bronze and plating layer were analyzed using a portable µXRF spectrometer (ArtTAX, Germany) under the settings of voltage 50kV, current 600µA, and time 120s. The inner structure of the sculpture was inspected through hard X-ray equipment (Smart EVO 300DS) under the settings of voltage 210kV, current 3mA, and time 40s.

Survey Results

Examination of Form

The Gilt-bronze Standing Bodhisattva stands straight on top of a lotus pedestal, holding a small bead with his right thumb and index finger and holding up his long, narrow strip of ornamental cloth with his left thumb and index finger. He wears a three-sided crown with an image of a transformed Buddha on the front side (Fig. 3-1). This suggests that the sculpture might have been produced and worshipped as a manifestation of Avalokitesvara Bodhisattva. Below both sides of the crown, strands of hair tucked behind the ears fall over the shoulders. The sculpture has a round face (Fig. 3-2), which is large in relation to the body. The eyebrows form gentle arches and continue to the ridge of the nose. The upper eyelids look almost straight towards the corners of the eyes, while the lower eyelids form crescent-shaped lines and meet the upper eyelids at the corners of the eyes. The ridge of the nose is straight, and the nostrils are not depicted. The philtrum is deeply indented. The upper lip is thin and forms a gentle curve, while the lower lip is plump. The lips are tightly pressed, and the corners of the mouth appear to be slightly lifted, giving the impression that the Bodhisattva is giving a gentle smile. The ears are small in relation to the large face. The short and thick neck has three horizontal grooves (Fig. 3-3). Behind the head, a peg for placing a mandorla still remains (Fig. 3-4).

Fig. 3-1. Transformed Buddha on the front side of the three-sided crown

Fig. 3-2. Face

Fig. 3-3. Neck and chest

Fig. 3-4. Peg for placing a mandorla on the back

Fig. 3-5. Right shoulder

Fig. 3-6. Left shoulder

The whole body is portrayed without a sense of proportion. The shoulders are narrow, but the arms are thick (Figs. 3-5 and 3-6). The right arm is folded almost to 180 degrees, and the right palm is facing forward (Fig. 3-7). The Bodhisattva is holding a small bead with his right thumb and index finger, while stretching out the rest of his three fingers which are stuck together. The left arm is naturally lowered down, with the wrist folded upwards almost at a right angle, and the palm facing downwards (Fig. 3-8). The deity is lifting a long, narrow strip of ornamental cloth with his left thumb and index finger. The yeongnak (瓔珞, strings threaded with large beads) is draped in the shape of an “X” over the front and back of the body, adding decorativeness to the sculpture (Fig. 3-9). The long, narrow strip of ornamental cloth is naturally flowing down from the shoulders on both sides of the body. The necklaces, bracelets, and drapery folds are expressed with shallow lines. The skirt falls down to the tops of the feet, and creases of the skirt are depicted with fine lines over the legs (Fig. 3-10). The left foot sticks out slightly forward (Fig. 3-11).

The pedestal is carved with a lotus blossom with eight petals, each of which is divided into two lobes (Fig. 3-12). The petals vary in size. The ones on the back are rather roughly formed.

Although this Gilt-bronze Standing Bodhisattva was buried and then excavated, the gilding remains rather intact, particularly on the backside. The statue’s round face and slightly pulled-in corners of the mouth are indicative of tender and gentle expressions in Buddhist sculptures from the Baekje Kingdom. Rust and peeled-off gilding around the eyes make the Bodhisattva look as if he is gently closing his eyes. Such an impression of the Giltbronze Standing Bodhisattva in harmony with gentleness creates an atmosphere of calmness, as if he is giving a soft smile. Despite simple depictions of necklaces and bracelets, this sculpture holds a strong decorative quality owing to yeongnak decorations draped over the front and back of the body which is one of its main characteristics.

The distinctive features of this sculpture, which is thought to have been produced in the Baekje Kingdom, include: a high crown, decorations with a pointed center over the neck, and a gentle smile (made by the pulled-in corners of the mouth). This Gilt-bronze Standing Bodhisattva sculpted to be viewed from all angles reflects a more advanced aesthetic sense than that of the Gilt-bronze Standing Bodhisattva from the temple site in Gunsu-ri, Buyeo (Figs. 4) which only was carved on the front. Moreover, it shows a soft and gentle smile on his round face and has a pedestal adorned with multiple petals of a lotus flower. Given all these aspects, the Gilt-bronze Standing Bodhisattva is presumed to have been produced after the seventh century CE in the Baekje Kingdom.

Fig. 3-7. Right hand

Fig. 3-8. Left hand

Fig. 3-9. Yeongnak decoration on the waist

Fig. 3-10. Legs

Fig. 3-11. Upper part of the pedestal and feet

Fig. 3-12. Lotus flower petal on the pedestal

Figs. 4-1 and 4-2. Gilt-bronze Standing Bodhisattva excavated from the temple site in Gunsu-ri, Buyeo (1. Front, 2. Back)

Because the small gilt-bronze Buddhist sculptures were more easily portable and replicable compared to middle- and large-sized gilt-bronze Buddhist sculptures, their excavation sites, production sites, and authenticity are always in question. The exact location where this Gilt-bronze Standing Bodhisattva was unearthed is unknown, but it is believed to have been found in Gyuam-ri, Gyuam-myeon, Buyeo-gun. In Gyuam-ri, Buddhist ruins from the Baekje Kingdom, including Wangheungsa Temple (王興寺), still remain. Verification of the exact excavation location of this Gilt-bronze Standing Bodhisattva will help to further develop studies related to the Buddhist ruins of Baekje.

Figs. 5-1 and 5-2. Inner side of the pedestal (1. Traces of spacers, 2. Trace of the sprue for pouring molten metal)

Fig. 6. X-ray image of the Gilt-bronze Standing Bodhisattva

Fig. 7. X-ray image of the Buddha Plaque excavated from Wolji Pond

Casting Method

The pedestal of the Gilt-bronze Standing Bodhisattva from Gyuam-ri is hollow inside (Figs. 5-1 and 5-2), and the traces of spacers or chaplets used to fix the internal core to the outer casting mold can be identified. There is also a trace of a sprue that the molten metal was poured through. These marks indicate that the molten metal might have been poured into the opening on the bottom of the sculpture’s pedestal while it was turned upside down so that it could flow into the head. This casting method is similar to the method commonly observed in ancient small gilt-bronze Buddhist sculptures.

X-ray analysis of the inner structure has identified bubbles which formed inside the arms and the pedestal during the bronze casting, yet were invisible to the naked eye (Fig. 6). These bubbles are thought to have failed to burst when the hot molten bronze was poured and have become solid instead. The Buddha Plaque unearthed from Wolji Pond in Gyeongju (Fig. 7) is a similar example of such a case. The bubbles are not visible on the surface of the plaque either, but the X-ray shows that they formed inside. Using X-ray analysis on the Gilt-bronze Standing Bodhisattva, cracks in both the thumbs and index fingers have been confirmed.

The use of spacers, the verification of a sprue for casting, and bubbles inside the sculpture attest that the Gilt-bronze Standing Bodhisattva was created using a lost-wax casting technique that was often employed to produce ancient small and mid-sized gilt-bronze Buddhist sculptures. This casting technique involves sculpting a layer of wax applied over an inner core of clay, covering the wax sculpture with the clay, adding heat to remove the wax, and pouring molten metal into the space where the wax was previously in place.

Component Analysis

The metallurgic composition of the Gilt-bronze Standing Bodhisattva is of copper (Cu), tin (Sn), and lead (Pb). The average composition amount, taken from three different tests, comes out to 82.6% copper, 14.1% tin, and 3.4% lead (Table 1). The inclusion of lead in the bronze artifacts often caused defects like the separation of the metal. Nevertheless, lead was often added intentionally to this type of sculpture to lower the melting temperature, facilitate the smooth flow of molten metal, and eventually form a distinct shape with well-defined decorations. Based on the previous compositional analyses of the gilt-bronze Buddhist sculptures, a blend of copper, tin, and lead, along with that of copper and tin, or copper and lead, is often found in the gilt-bronze Buddhist sculptures produced in the sixth and seventh centuries CE during the Three Kingdoms period. Several small, gilt-bronze Buddhist sculptures show similar proportions for their bronze alloy. According to the component analysis of the base metal layers of the gilt-bronze Buddha sculptures at the Gyeongju National Museum (Figs. 9–12), Silla gilt-bronze Buddhist sculptures produced in the seventh century CE—when the Gilt-bronze Standing Bodhisattva was created—also contain 4–7% of lead (Table 2). The small gilt-bronze Buddhist sculptures produced in and after the eighth century CE during the Unified Silla period, however, contain almost no lead. They were made from an alloy of copper and tin or made of pure copper. This indicates that by the eighth century CE, owing to the development of better reforging techniques, sculptures were produced at higher temperatures using high-purity bronze.

Figs. 8-1 and 8-2. Analysis locations of the Gilt-bronze Standing Bodhisattva (1. Front, 2. Back)

Fig. 9. Gilt-bronze Buddha Triad with a Large Mandorla

Fig. 10. Gilt-bronze Standing Buddha

Fig. 11. Gilt-bronze Standing Bhaisajyaguru Buddha

Fig. 12. Gilt-bronze Standing Buddha

Gold (Au) and mercury (Hg) were detected in the gilding layer, indicating that the method for plating the surface of the Gilt-bronze Standing Bodhisattva was a mercury amalgamation technique. This technique was mainly used when gilding ancient metalware, including gilt-bronze Buddhist sculptures. Whether or not the gilding layer of a gilt-bronze Buddhist sculpture contains mercury serves as a critical clue for guessing which plating technique was applied. The gilt-bronze Buddhist sculptures from the Three Kingdoms and Unified Silla periods were commonly gilded using a mercury amalgamation technique, where gold was melted and amalgamated into mercury. This mixture is then applied to the surfaces of a sculpture, and—by heating the surfaces—only the mercury is evaporated. Other plating techniques include the application of gold leaf using mercury as an adhesive and heating it, as well as a hand application of thin gold leaf to an adhesive layer of organic materials, like lacquer varnish or glue, over the base metal. The former technique was employed in the gilt-bronze Buddhist sculptures from the Unified Silla period. Both gold and mercury (Table 2) were found during the component analysis of the Gilt-bronze Standing Vairocana Buddha in the National Museum of Korea (Figs. 13). The rear side of the sculpture exhibits square gold leaves attached to the surface. This statue serves as a reference for the study of surface treatment techniques used in Buddhist sculptures.

Figs. 13-1 and 13-2. Gilt-bronze Standing Vairocana Buddha (1. Front, 2. Rear-side)

Conclusion

This paper aims to analyze the Gilt-bronze Standing Bodhisattva crafted in the Baekje Kingdom in the seventh century CE and excavated from Gyuam-ri in Buyeo to identify its shape, structure, and casting technique. This statue strikes an unusual pose by holding a small bead in its right hand and lifting a long, narrow strip of ornamental cloth with its left hand. The yeongnak draped in an X-shape at the front and back of its body features strong decorativeness. A close examination of the shape of this sculpture has found that it bears characteristics of the Bodhisattva sculptures produced in the Baekje Kingdom, including ornaments such as a three-sided crown and a soft, gentle smile. Accordingly, it is presumed to be an Avalokitesvara Bodhisattva sculpture created in the Baekje Kingdom in or after the seventh century CE, during the Sabi period.

Traces of spacers used to affix the interior core to the outer casting mold and those of a sprue for pouring molten metal were found inside the pedestal. Moreover, bubbles formed during casting were observed inside the arms and the pedestal. The use of spacers, the identification of the sprue, and bubbles inside the sculpture all suggest that the Gilt-bronze Standing Bodhisattva was produced by using a lost-wax casting technique. This method is often used to cast ancient small and mid-sized gilt-bronze Buddhist sculptures.

The base metal of the Gilt-bronze Standing Bodhisattva consists of a blend of copper, tin, and lead, commonly observed in the sixth- and seventh-century CE gilt-bronze Buddhist sculptures of the Three Kingdoms period. The lead appears to have been included intentionally to increase the castability of the bronze and allow for detailed patterns and decorations to be clearly depicted. The alloy composition of copper, tin, and lead is one of the common blends used during the Three Kingdoms period, as demonstrated by the existing analysis results of gilt-bronze Buddhist sculptures. The small gilt-bronze Buddhist sculptures produced in and after the eighth century CE during the Unified Silla period, however, were chiefly made of pure copper or an alloy of copper and tin with nearly no lead, indicating that the development of better reforging techniques led to the production of the gilt-bronze Buddhist sculptures at higher temperatures with high-purity bronze.

The detection of mercury in the gilding layer of the surface of the Gilt-bronze Standing Bodhisattva suggests that the sculpture was gilded using a mercury amalgamation plating technique that dissolved gold in mercury. As shown by the Gilt-bronze Standing Bodhisattva, this plating technique was a surface treatment method principally used while crafting giltbronze Buddhist sculptures on the ancient Korean Peninsula.