Circular tray with three ring-form-feet and five cups

Five matching cups, each with wide, rimless mouth and sides tapering inward to small, slightly splayed circular foot; large circular tray with short, gently rounded sides and three ring-form feet attached to the base at equidistant intervals; white porcelain with transparent glaze tinged with pale celadon green; bases of cups unglazed and each marked with the ideograph 波 (bo) brushed in red ink on the base after firing; the center of the tray base unglazed. From northern China; Hebei or Henan province.