Cast "Yachou" vessels have often been excavated from Suputun in Itu, Shandong, so scholars believe that "Yachou" represents the "Poku" clan mentioned in the ancient "Zozhuan" text. Flourishing in the late Shang period, this clan was exterminated by King Cheng in the early Western Zhou. About forty percent of the surviving cast vessels inscribed with "Yachou" are rectangular vessels, sharing along with rectangular vessels excavated from the tomb of Fuhao renown in the developing splendor of late Shang bronze vessel shapes.

 

The curving sides of this vessel are divided into four transitions. The mouth rim is wide and flaring, constricting down to form the neck area, which then flares out for a diagonal to create the shoulders. The outline extends down for the body, which then flares out again for the base. This makes for a shape with numerous transitions and flange angles.