Sang de boeuf was one of a number of new "flambé" glazes, marked by "unpredictable but highly decorative and varying effects",[1] developed in the Jingdezhen porcelain kilns during the Kangxi reign (1662–1722).
[2] According to one scholar: "In its finer examples, this spectacular glaze gives the impression that one is gazing through a limpid surface layer, which is slightly crazed and strewn with countless bubbles, to the color that lies underneath".
From the late 19th century onwards, usually after lengthy experiment, many Western potters produced versions of the Chinese glaze, which is technically very difficult to achieve and control.
This suggests the close personal interest some emperors took in the imperial potteries, and also that some secrets must have been restricted to a small group of potters.
[12] Where the Xuande sacrificial red pieces have a very subtle mottled coverage, sang de boeuf was produced with a variety of shades of colour and as well as mottling, streaked effects in the glaze, which often fades to white at the top of pieces, and conversely thickens around the shoulders of vases and at the foot, which is often not fully covered by the glaze.
[1] The great number of very sensitive variables meant that the glaze colour and effects were initially not reliably controlled by the makers, leaving an element of randomness that appealed to Chinese aesthetics.
[15] In the 19th century various Western potters, especially in the emerging art pottery movement, tried to copy the Chinese glaze, which had acquired a great reputation, but found replicating it very difficult, whether in porcelain or stoneware.
[23] The American ceramist Fance Franck (1931–2008) extensively researched copper red glazes in her workshop in Paris leading to the rediscovery of the Ming technique.