Lot 117. A 'Cizhou' ribbed bowl, Northern Song dynasty (960–1127). Estimate 5,000 — 7,000 USD. Photo Sotheby's

of U-shaped form, the almost straight sides rising from a broad straight foot ring to an unglazed rim, the exterior encircled by a band of broad knife-cut vertical grooves, the interior and exterior covered with an almost colorless glaze over a white slip, stopping unevenly above the foot to reveal the buff body. Diameter 4 3/4  in., 12 cm

Sotheby's. Important Chinese Art, New York, 13 sept. 2016, 10:30 AM