Such a ceramic is covered with a dark brown glaze with high iron content. Adjusting the parameters of the furnace is much sophisticated. The transition more or less slow between solid and liquid during heating and the reverse transition when cooling generate texture effects that are much refined, such as the hare's fur or partridge's feather.
The chaos that followed the fall of the Tang did not remove the Chinese taste for a continuity of artistic traditions. On September 16 in New York, Sotheby's sells an archaistic jar with black glaze made during the Song era although its dating cannot be better identified.
It is a pot of bulbous shape 20.5 cm high whose opening is wider than the base. The rim and the foot are not glazed, as it is often the case at that time. In some places the iron of the glaze created an effect of spray russet droplets that was certainly intended by the potter.
The decoration made with a brush over the glaze is also archaic, with four wide russet spirals.
This piece known as the Vortex Jar with some features of a high rarity is estimated $ 2.5M, lot 3.
I invite you to play the video shared by Sotheby's :