W:6.7cmA Lemon Yellow Glazed Cup, Yongzheng six character markfinely potted with rounded sides rising from the straight footrim, glazed to the exterior with a fine glaze of bright lemon tone, the interior and the inside foot and base white glazed, the base bearing the nianhao, written in underglaze blue within a double ringProvenance: Belgium Private Collection来源：比利时私人收藏Delicately potted with deep rounded sides resting on a short straight foot, the exterior applied with a vibrant lemon-yellow glaze stopping neatly at the foot, the base inscribed with a six-character reign mark within a double-circle. Deceptively simple in form and colour, lemon-yellow glazed vessels represent one of the most technically challenging porcelains to be produced. Monochrome wares of this type required absolute precision in potting, glazing and firing, as the smallest imperfection resulted in the destruction of the piece. Amongst all the different monochrome glazes, yellow is the only colour that has direct imperial association. Although imperial yellow-glazed wares had been produced from the early Ming dynasty they were used exclusively for ritual ceremonies; thus lemon-yellow vessels provided the court with an alternative for daily use. The yellow glaze was derived from an antimoniate oxide and the lemon-yellow glaze was a Yongzheng innovation achieved when the antimoniate of iron was combined with tin oxide resulting in a dazzling translucent yellow hue. A pair of closely related lemon-yellow glazed bowls, from the collection of Mr and Mrs Eli Lilly, was sold in Sotheby's New York rooms, 3rd June 1993, lot 334. Compare also a similar small bowl sold at Sotheby's Hong Kong, 6th April 2016, lot 3603.