According to Kewpie's official website, mayonnaise was first introduced to Japan in 1925. Since then, Kewpie mayo has been one of the predominant household condiments there. People often use it on vegetables and as a salad dressing. Kewpie is a smoother, creamer mayonnaise, and it's made with rice vinegar rather than distilled vinegar. Its popularity in Japan really can't be overestimated.