Based on the trademark inside the case, this ring is believed to be made by the jewelry house Marret Frères, which traces its roots to a company founded by Pierre Marret in Paris at the end of the 18th century. The three-stone ring, which includes a colored diamond in the center setting, is thought to have been used for formal occasions. After the passing of Princess Nobuko, it was kept by individuals related to the Asaka family. Marret Frères was absorbed by Bancelin, another jewelry house, in 1912.