Nine-hundred-year-old stone dish used in  Imperial Chinese court and worth up to £1.5m is found in British Museum collection after being dismissed as Korean bowl worth £1,500

  • Ru ware was produced for the exclusive use of the Song dynasty imperial court
  • It was only manufactured for a very short period of time from 1086–1125 CE
  • Production stopped when access to the Great Kiln in Qingliangsi was lost
  • Items of Ru ware are typically — but not always — a ‘duck egg’ or ‘sky’ blue 
  • Many have tried to replicate the glaze, many in the Korean ceramic tradition

A blue–green dish held in the British Museum — long thought from Korea — has been shown to be one of less than 100 known pieces of the rarest type of Chinese pottery.

Dating back some 900 years to the time of Imperial China’s Song dynasty, ‘Ru official ware’ was noted for its lack of decoration and typically pale, ‘duck-egg’ blue glaze.

Produced only for a short period between 1086–1125 CE, Ru ware was produced exclusively for the use by members of the Northern Song Imperial court.

According to experts, the secret to Ru ware lay in its manufacture at the ‘Great Kiln’ of Qingliangsi, in Henan, which had access to clay of a particular composition. 

Since its introduction, there have been many failed efforts by potters to reproduce the special, ‘crackled’ glaze effect — particularly in the Korean ceramic tradition.

Like many of these efforts, the small, brush washer dish is not of the iconic blue most associated with Ru ware — although such did come in shades all the way to green.

It also sports relatively chunky spur marks (left by the supports in the kiln), quite unlike the tiny, seed-sized spurs commonly seen in Ru ware ceramics. 

For these reasons the item — believed genuine by collector Sir Percival David on acquiring it in 1928 — was dismissed as a Korean imitation around half-a-century ago.

However, fresh analysis by Far Eastern ceramics expert Regina Krahl suggested that the little dish was indeed a genuine Ru ware — prompting forensic chemical analysis.

Cranfield Forensic Institute experts performed non-destructive X-ray fluorescence analysis of the dish, comparing this with scans of real Ru ware and Korean imitations.

They found that the dish’s trace element ‘fingerprint’ matched those of the real thing— making the piece an unusual but nevertheless authentic piece of official Ru ware.

A blue–green dish in the British Museum — long thought from Korea — has been shown to be one of less than 100 known pieces of the rarest type of Chinese pottery


Dating back some 900 years to the time of Imperial China’s Song dynasty, ‘Ru official ware’ was noted for its lack of decoration and typically pale, ‘duck-egg’ blue glaze. Produced only for a short period between 1086–1125 CE, Ru ware was produced exclusively for the use by members of the Northern Song Imperial court. Pictured: the newly-confirmed Ru ware dish

According to experts, the secret to Ru ware lay in its manufacture at the ‘Great Kiln’ of Qingliangsi, in Henan, which had access to clay of a particular composition. Pictured: other examples of Ru ware, including (from left to right) a dish, a bottle and a bowl stand

X-RAY FLUORESCENCE

X-ray fluorescence spectroscopy is a non-destructive technique used to determine the chemical composition of the materials it analyses.

It works by exciting the sample with X-rays and measuring the secondary X-rays produced as a result. 

Each element in the sample gives off a characteristic X-ray fingerprint, which allows it to be identified. 

‘Regina Krahl’s experienced eye alerted us to re-examine the dish — which is smaller than an adult’s hand,’ said the British Museum’s Chinese ceramics curator Jessica Harrison-Hall.

‘When compared to other “Ru” wares in the collection, the cut of the foot ring, the shape of the brush washer and the ice-crackle within the glaze looked convincing.

‘But the colour of the glaze was quite grey and the marks on the base much larger than the usual sesame-seed shaped ones.

‘So. to be certain. the scientists were called in. They proved that she was right and another “Ru” ware existed. These are incredibly rare, beautiful and ancient — made just 20 years after the Battle of Hastings.’ 

‘It was a pleasure to be able to employ our analytical techniques on such important and rare examples of Chinese ceramics,’ added Cranfield Forensic Institute director and archaeologist Andrew Shortland.

‘There is great potential for art historians, curators and scientists to work together to confirm the attribution of important problem pieces.

‘I hope that this work will inspire further joint projects,’ he concluded.

‘We are thrilled that this imaginative collaboration between the Museum’s Chinese ceramics specialists and Cranfield’s forensic analysts has reconfirmed Sir Percival’s ground-breaking scholarship nearly 100 years on,’ said Sir Percival David Foundation chairman Colin Sheaf.

‘This enables our exceptional brush washer to rejoin the Foundation’s unequalled group of “Ru” wares.

These, he added, are ‘the greatest treasures within this unparalleled private collection now superbly displayed in its entirety at the British Museum.’

According to experts, the secret to Ru ware lay in its manufacture at the ‘Great Kiln’ of Qingliangsi, in Henan, where the humidity affected the ceramic firing process

CHINESE RU WARE POTTERY

Pictured: a close-up of a Ru ware dish, showing the iconic crackle in the glaze

Ru ware is the rarest type of Chinese pottery that was produced for the exclusive use of the Song dynasty imperial court from 1086–1125 CE.

They typically comprise small items — like dishes used for washing ink brushes, cups and carafes — and were undercoated save for a glaze which typically (if not always) took on a ‘duck egg’ blue hue.

These ceramics were later described by the Qianlong Emperor (who ruled China from 1736–1795 AD) — an avid collector of Ru ware — as being ‘as rare as the stars at dawn’. 

According to experts, the secret to Ru ware lay in its manufacture at the ‘Great Kiln’ of Qingliangsi, in Henan, which had access to clay of a particularly unique composition — believed by some experts to have contained dissolved iron oxide with a very low amount of titanium dioxide.

Imperial access to the kiln site at Qingliangsi was lost, however, after armies invaded Northern China — forcing the court to flee southwards.

Despite having access to many of the original craftsmen, the Song dynasty was unable to replicate the magic of the Ru ware after relocating.

Since its introduction, there have been many failed efforts by other potters to reproduce the special, ‘crackled’ glaze effect — particularly in the Korean ceramic tradition, as well as under the reign of China’s Yongzheng Emperor in the early 18th century, where they were copied in imperial Jingdezhen ware.

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