Vintage Heartland International Stoneware 9" Serving Bowl set of 2 Japan. This two-piece set of round serving bowls features a Heartland pattern in a multicolor design. Made of stoneware by International China in Japan during the 1980s, these Mid-Century Modern bowls are both decorative and practical. They are oven, microwave, and dishwasher safe, with a glossy finish, suitable for all occasions.