9" tall, chip on top rim............. "sang-de-boeuf" (ox blood) were in use by the Chinese from the 11th century, and the effect was achieved by using copper oxide as a colouring agent and firing the object in a reducing atmosphere. In the 18th century the red glaze often accumulated on the shoulders of vases and bowls, reproducing the effect of coagulated blood. Sometimes the glaze was often slightly streaked, or included blue bleeds and wares with these features were prized by collectors in the 19th century