A Sanxingdui conservator and the bronze that won't sit still

We arrived at the Sanxingdui conservation building a little before nine, on a flat grey morning in early March, when the camphor trees along the access road were dripping from an overnight rain. The laboratory sat behind the new museum hall, low and concrete, ventilated by a quiet bank of HEPA units whose hum was the first sound we heard inside. Wang Xiulan was already at her bench. She did not look up. She was bent over a fragment the size of a pear, holding a fibre brush in her right hand and a small dental pick in her left, and the brush was moving in slow horizontal passes across the bronze the way a person dusts a sleeping child's face.

She had been at the bench since seven. The fragment, she told us later, had come out of Pit Three in 2021 and had been waiting for her since November.

The bench itself was unremarkable. A binocular microscope on a swing arm. A tray of fibre brushes arranged by stiffness. Two dental picks, a set of bamboo skewers sharpened at one end, a small bottle of deionised water, and a glass jar of cyclododecane crystals that she would melt later in a double boiler and paint onto loose fragments to hold them in place during transport. There was no drama in the layout. It looked like a dentist's tray with the chrome removed.

The fragment in front of her was part of a face. The eye, almond and protruding, had already been freed from its packed crust of red earth and copper salts. The cheek was still buried. She worked outwards from the eye, a millimetre at a time, lifting soil from the bronze with the pick and brushing the loosened grains into a small tray to her left, where they would be bagged, labelled, and sent for analysis to a soil lab in Chengdu. Nothing was discarded. The dirt, she said, was also the artefact.

“A few more months in her hands was not the part of the timeline that was hurrying.”

Wang is forty-four. She trained at the Central Academy of Fine Arts in metals conservation, then at the Shanghai Museum's laboratory, and came to Guanghan in 2019, before the new pits were opened. Six fresh pits had been confirmed by the end of 2020, and the lab had effectively doubled its caseload in a single season. The team is now nineteen conservators, most of them in their thirties, working in two shifts six days a week. We had asked, over tea on the previous afternoon, whether the pace felt frantic. She had thought for a while and said that the pace felt accurate. The bronze had waited three thousand years. A few more months in her hands was not the part of the timeline that was hurrying.

What she was doing at the bench was reading. The patina on a Sanxingdui bronze, the green and red and black skin of corrosion that has grown over the metal in the soil, is not noise to be cleaned away. It is data. The colour, the texture, the way it sits on the underlying surface, all of it records what the object has been doing for the past thirty centuries. A patch of cuprite under malachite tells her the burial chemistry was reducing for a long time. A bloom of paratacamite tells her chlorides got in, probably from a flood. She works to preserve the patina, not to remove it, and only lifts what hides the form underneath.

We asked, while she paused to swap brushes, what the work felt like from inside the question. She knew which question we meant. For most of the twentieth century, the standard sentence in Chinese archaeology placed the Bronze Age firmly in the Yellow River valley, with the Shang and the Zhou as its origin and centre. Sanxingdui, when the first pits were uncovered in 1986, complicated that sentence. The new pits, opened between 2020 and 2022, complicated it further. The bronze masks and the gold staff and the seventh-century-BCE altars from this part of Sichuan are unmistakably not Shang in style. They are something else, and they are very old, and they push the geography of early Chinese civilisation south and west of where the textbooks had it.

Wang said the conservators do not, on the whole, argue about this in the lab. They argue about whether a particular fragment was originally part of a head or a standing figure, and about whether a given alloy ratio matches Pit Two or Pit Three, and about whether a hairline crack should be consolidated with Paraloid B-72 or left alone. The larger argument, she said, will be made by scholars who read what she sends them, in papers written long after she has gone home for the evening. Her contribution to the argument is to make sure the evidence arrives in a condition that can still be read.

Late in the morning, she freed the rest of the cheek. The face, now visible in profile, was about the length of a hand. The eye protruded almost three centimetres from the surface, an exaggerated almond with a narrow incised pupil, and the brow above it rose in a single clean ridge that ran back into the temple. There was a small notch at the corner of the mouth that we had not seen on the published photographs of similar masks, and Wang noted it on a clipboard in three short characters. The notch, she said, might be original and might be damage. The metallography would tell. She covered the fragment with a piece of acid-free tissue and a small weighted board, and stood up to stretch her back.

We walked outside for a few minutes. The rain had stopped. A school group was just arriving at the museum gate, and from the courtyard we could hear a guide explaining, in a brisk and confident voice, what the bronzes meant. Inside the lab behind us, the HEPA units kept humming, and the fragment of a face from a kingdom whose name we still do not know sat under its tissue, waiting for the afternoon.