A fine blue and white 'bajixiang' washer seal mark and period of Qianlong

finely potted, delicately painted in the Ming-style in vivid tones of cobalt-blue, the interior decorated with a large central stylised floral medallion, issuing eight lotus flowers, encircled by the bajixiang, the low upright sides with an upright trifoliate band, below a band of classic scroll at the rim, the exterior decorated with a composite floral meander below a band of scrolling lingzhi, separated by a raised fillet, the base counter-sunk and inscribed with the six-character seal mark in underglaze-blue