Nyuzen Jumbo Watermelon

Nyuzen Jumbo Watermelon (Nyuzen Jumbo Suika) is a watermelon variety cultivated in the town of Nyuzen, located in Toyama Prefecture, Japan, and officially registered as one of the country’s Geographically Indicated (GI) products.

The Nyuzen Jumbo Watermelon is a large watermelon, typically weighing between 17 and 19 kilograms—nearly double the weight of traditional Japanese large watermelons, which average 7 to 9 kilograms. It is recognized by its distinctive rectangular shape and dark green, striped rind. Its flavor is sweet, leaving a lingering sweetness in the mouth. Its shape, size, and aroma have made it a well-known regional product. It is commonly used in local festivals and events and is also given as an “ochugen” gift during summer to express gratitude. The primary variety used in cultivation is “Nyuzen Jumbo,” though equivalent varieties with similar characteristics may also be selected.

The production area for this watermelon is confined to the town of Nyuzen in Shimoniikawa District, in the northeastern part of Toyama Prefecture. The region is surrounded by the Hida Mountains and lies on a broad alluvial fan shaped by the Kurobe River. The soil consists of sandy, shallowly tilled soils ideal for watermelon cultivation. The low water retention capacity of these soils allows watermelons to grow slowly under high humidity, resulting in large, heavy fruits. Cultivation techniques are critical to ensuring optimal growth: plants are spaced more than 60 centimeters apart, and no more than two fruits are permitted per plant to concentrate nutrients in the harvested melons. Special umbrellas made from rice straw are used to shield the fruits from sunburn damage. To prevent soil degradation from repeated planting, fields are left fallow for at least six years after each planting cycle. Watermelons must weigh at least 9 kilograms before being released to market.

The history of cultivating large watermelons in this region dates back to approximately 1897. Over more than a century, cultivation techniques have evolved, leading to innovations in soil improvement, pest control, and fruit enlargement. Large watermelon cultivation, which began during the Meiji period, was even exported abroad during the Taisho period, with cultivation covering 96 hectares at its peak. However, in subsequent decades, war and shifting consumer preferences reduced the cultivated area. In 1971, a cooperative was established to improve quality and share cultivation methods, and in 1982 it was renamed the Nyuzen Town Jumbo Watermelon Production Cooperative. Around 1983, locally grown watermelons began to be marketed under the brand name “Nyuzen Jumbo Watermelon.” Traditionally packed in woven rice-straw bags originally used for storing rice, these watermelons are still sometimes packaged today in special containers made from touched rice straw.