An unusual wucai 'dragon' bowl mark and period of Longqing

well potted with shallow rounded sides, painted with red, green, black, yellow and turquoise enamels and underglaze-blue on the interior with a five-clawed dragon writhing among cloud scrolls, within a double-line border repeated at the rim, the exterior with six large stylised flower roundels with interlocking lotus petals, divided by cloud scrolls, between double line borders, the base inscribed with the six-character mark within a double-circle in underglaze-blue