Yellow is the colour of the sun and of gold, and where it reads as gold it is among the most exalted of colours: the gold ground of Byzantine and medieval icons signifies divine, uncreated light, and gilding marks the sacred across many traditions. In China yellow was the imperial colour, reserved at times for the emperor, associated with the centre and with earth in the five-phase system. Yet yellow has a persistent shadow side in the West. It became the colour of cowardice, treachery and disease: Judas is often shown in yellow in medieval art, quarantine flags were yellow, and yellow was repeatedly used to mark out stigmatised groups, most notoriously in the badges imposed on Jews from the medieval period through the Nazi era. This double life, solar glory as gold, contempt as pale yellow, is one of the sharpest examples of how a single hue carries opposite values by shade and context. In the modern chakra scheme yellow is the solar plexus, a recent assignment.