Origin of Production: Yamaguchi Prefecture, Japan
Category: Zakkan-Rui (Japanese for “citrus created through natural crossbreeding”).
Harvest Seasons: The Iyokan citrus season typically lasts from January to March, with 90% yielding a variety called Miyauchi Iyokan. Each fruit is carefully analyzed for ripeness with a sensor, which is also used to determine the sugar content (only Iyokan with a sugar content of 11.5 % or higher is sold on the market). Iyokan citrus harvested in March is considered “aged” Iyokan and results in a high-quality exotic Japanese fruit product called Yayoi Beni.
Shape / Size:
Similar in shape, size, and color to mandarins, the Iyokan citrus measures 8-10cm in diameter and weighs 200-280g. The fruit has an oblate or oval shape and glossy, textured skin.
Taste profile: The Iyokan citrus fruit is revered for its blend of sweet, tangy, and sour notes. Like mandarins, Iyokan has thicker than average skin that is easy to peel and offers a decent sugar-acid balance. Iyokan harvested from January to February imparts a good grain, and even after peeling, the fruit remains firm and intact. Yayoi Beni, or aged Iyokan citrus, harvested in March, is characterized by its mild, non-acidic flavor and soft and juicy grains on the skin.
Other features and trivia:
- Iyokan is rich in vitamins C, A, E, folic acid, pantothenic acid, niacin, potassium, magnesium, copper, and calcium, which gives it natural properties for preventing colds, recovering from fatigue, enhancing organ function, and purifying blood.
- Although its exact origin is unknown, Iyokan citrus is widely believed to be a hybrid of Japanese tangerines (Dancy) and oranges (Kaikoukan).
- Iyokan citrus fruits are the second most commercially produced citrus.
- In Ehime Prefecture, Iyokan were initially grown in wooden pentagon molds to symbolize good luck for students during exam periods.
- The name was inspired by the Japanese word “Iiyokan,” which translates to “good feeling.”
Iyokan from Yamaguchi Prefecture
Iyokan citrus was first discovered in Hagi City, Yamaguchi Prefecture, during the Meiji period (1968-1912). It was then brought to the Ehime Prefecture and named “Iyo” (after the prefecture’s traditional name, “Iyo-no-Kuni”), where it is still widely cultivated. By the 1990s, Iyokan from Ehime Prefecture became one of the region’s most popular exotic Japanese citrus varieties. Today, Iyokan citrus is harvested in Ehime, Wakayama, and Hiroshima.
Within Ehime Prefecture, it is mainly harvested in Matsuyama City, Imbari City, and Yawatahama City. Due to the increasing variety of citrus and lack of popularity, fewer people across Japan are planting Iyokan trees than before—the 2018 peak season harvest resulted in a mere 27,000 tons, compared to 157,000 tons in the 1990s.
Regular Iyokan vs. Miyauchi Iyokan
The most commonly available varieties of Iyokan can be divided into “regular Iyokan” and “Miyauchi Iyokan.” Originally discovered by Mr. Masaji Nakamura in his garden, regular Iyokan citrus was initially named “Anato mandarin” due to its similarity to the mandarin fruit. Several years later, Mr. Yishimasa Miyauchi purchased one of Mr Nakamura’s trees and planted it in his garden in Ehime Prefecture.
The coastal, sunny climate and mineral-rich soil resulted in a new variety, Miyauchi Iyokan, named after its founder, Mr. Miyauki. Since its discovery in 1955 in Hirato-cho, Matsuyama City, Miyauki Iyokan has become one of Ehime Prefecture's most popular and widely cultivated varieties. To preserve the pronounced sweetness and characteristic thin skin, Miyauchii Iyokan’s production methods have not changed since its first discovery. The Miyauchi Iyokan mother tree continues to be carefully managed and designated as a natural monument by Matsuyama City.
Miyauchi Iyokan is harvested in December and shipped from mid-January to mid-March after a specialized storage routine. This enriches the fruit's skin color and balances acidity, resulting in a fruit rich in color, taste, and aroma.