The watermelons, produced exclusively in Zentsuji, Kagawa Prefecture, are grown in square plastic containers. They are inedible as they are harvested unripe.
Production began about 45 years ago and currently there are six growers, with a total of 330 watermelons expected to be shipped on the first day.
Department stores and fruit stores in Japan sell the watermelons as popular ornaments, while the distinctive item has also caught on abroad, with orders from countries like Thailand and Russia.
