Mishima Bareisho

Mishima Bareisho is a potato variety produced in the regions of Kannami Town, under Mishima City and Tagata District, in Shizuoka Prefecture, Japan, located on the western slopes of Mount Hakone, and registered under the Japonya GI (Japan GI mark) system as a geographical indication product.

The product belongs to the "May Queen" variety and is registered under the category of Vegetables, within the broader group of Vegetables/Cereals/Legumes, with registration number 18. Mishima Bareisho is defined by its unique sensory characteristics, the geographical conditions of its growing region, and specific post-harvest processing methods.

Morphological and Sensory Characteristics

Mishima Bareisho has a smooth, attractive and glossy exterior surface. Its textural properties stand out by combining qualities of two distinct potato varieties:

1. "May Queen"-like Texture: Like the "May Queen" variety, it maintains a creamy consistency when cooked and does not easily break apart.
2. "Danshaku" (Baron)-like Mouthfeel: The mouthfeel is described as soft and mealy/powdery, similar to the widely cultivated Japanese "Danshaku" (Baron) variety.
3. Flavor: It offers a sweet flavor profile, reminiscent of the "Danshaku" variety.

Geographical Location and Soil Structure

The geographical production area of Mishima Bareisho lies on the western slopes of Mount Hakone. The soil structure of this region consists of layered deposits that, over a long period, have transformed into black weathered soils derived from volcanic ash, historically known as "black soil."

The cultivated soil layer is deep and soft. This structure imparts excellent permeability, aeration, and water retention properties to the soil.

Climate Conditions

The region’s climate provides suitable conditions for potato cultivation:

• Germination Period (February–March): When the soil surface is covered with mulch, ground temperatures range between 10 and 15°C.

• Growth Season: During the subsequent growth season, average daily temperatures range between 13 and 20°C.

• Precipitation: A moderate rainfall pattern throughout the growing period prevents excessive soil drying.

These conditions are considered ideal for potato cultivation, which requires moderate humidity and a mildly cool climate.

Topography and Cultivation Methods

The south-facing sloped structure of the fields in the production area provides two key advantages that enhance suitability for potato farming: extended daylight hours and effective drainage. However, this sloped terrain makes the use of large harvesting machinery difficult. As a result, each potato is carefully harvested by hand.

During cultivation, the soil surface is covered with a vinyl mulch. Harvesting is performed with great care to avoid damaging the potato skin.

Post-Harvest Processing: Curing and Drying

One of the critical steps determining the quality of Mishima Bareisho is the post-harvest curing and drying process. Harvested potatoes are stored for one to two weeks in a cool, dark, and well-ventilated environment to dry. This process provides several benefits:

• Enhanced sweetness.
• Development of a soft, mealy texture.
• Extended storage life.

This drying process is essential; if potatoes are stored before their surface is adequately dried, moisture condenses on the skin and respiration is impaired. This can lead to bruising, rotting, and disease. By exposing the potatoes to air during drying, their quality is preserved even after purchase by consumers.