Glazes containing copper which turn red when fired in a reducing atmosphere. The earliest known copper-red glaze occurs on wares made in Shanxi during the Tang dynasty. Jun kilns of the Song dynasty commonly used copper glazes. The sacrificial xianhong of the early Ming dynasty and its Qing dynasty copies, the Qing dynasty jihong (same but of the period), langyaohong, Peach-bloom and the Qing Jun red, which was really a monochrome red of the flambé type are all copper based red glazes. Since copper is very volatile it is very difficult to fire a glaze based on copper so as it turns out pure red when finished. The success rate of wares with specifically copper red glazes was typically very low.