Although the box inscription and the signature on the base of the bowl itself represent the bowl as the work of the famed Kyoto ceramic artist Kenzan, it is no understood to be a later work in the pervasive and enduring Kenzan style. The bowl had been broken in Japan and repaired with gold-sprinkled lacquer. The motif of cormorant fishing suits this bowl to use in the summer months when cormorant fishing takes place on Japanese rivers, but in modern usage it would be classified not as a "summer tea bowl" but as a bowl for preparation of "thin tea" (usucha). It may have been made originally as part of a set of lidded bowls for serving food.
Source: Louise Allison Cort, "Mrs. Gardner's 'Set of Tea-Things,'" in in Journeys East: Isabella Stewart Gardner and Asia, edited by Alan Chong and Noriko Murai (Boston: ISGM and Gutenberg Periscope, 2009): 395.