Judging by the tomobako, the shifuku, and the patina of the bowl, this piece was likely fired in early Showa (1926 - 1936) when Sosen was thought to be most active.
Perfectly formed and resting firmly on a well-grounded kodai (foot/ pedestal), this chawan is vivid, light in the hand, and has a calming presence. The artist, Asao Sosen (1897 - 1978), was known for making chagama furo (Japanese ornamental brazier used in tea ceremony) as well as “Unge” stoneware of various forms. Unge-ware uses a technique where black and grey ash glaze is applied to the pieces during firing to give works made in this way a cloudy appearance. Unge originated in the Fukakusa area of Fushimi—a suburb of Kyoto proper. Examples of Sosen’s work are held by The National Museum of Modern Art in Tokyo.
This piece is 5.5 inches in diameter (14cm) and stands 2.4 inches tall (6cm). It is in excellent condition and comes with a patterned cloth shifuku and a tomobako bearing the artists signatrure. The characters 宗筅 (Sosen) can be clearly seen impressed into the base of the tea bowl.