Tianqi Emperor
Tianqi porcelain or ko sometsuke refers to Chinese underglaze blue porcelain made in the unofficial kilns of Jingdezhen (景德镇) for a largely Japanese market in the 17th century. The term "Tianqi" (天啓; "tenkei" in Japanese) is a reference to the era name of the reign of the Tianqi Emperor (r. 1621-1628) in the late Ming Dynasty, but the style and the name are not limited to his reign. Over the same period the related Transitional porcelain was being made.